Solution Manual for Essential Statistics, 2nd Edition

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Chapter 1 Test A1-1Chapter 1 Test A - Multiple ChoiceSection 1.1 (What are Data?)1.[Objective: Understand data.] Data can be defined asnumbers in context. Suppose you are given thefollowing set of numbers:1.73, 1.83, 1.57, 1.88, 1.70, 1.65What additional information would allow you to define these numbers as data?a.Units of measurement. This could represent the heights of six 5-year-olds, in meters.b.Units of measurement. This could represent the heights of six 20-year-olds, in meters.c.We need to know where these numbers were collected.d.We need to know who collected these numbers.Section 1.2 (Classifying and Storing Data)2.[Objective: Understand methods for coding categorical variables.]According to the following datatable, which variable(s) is (are) categorical?AgeGenderWeightEthnicity23118011801260200139219115412012023a.None are categorical because there are only numbers in the tableb.Age, gender, and ethnicityc.Gender and ethnicityd.Gender3.[Objective: Distinguish between stacked and unstacked data.]The following data table is organizedusing which method?Men’s AgesWomen’s Ages35423933413737354039a.This is stacked data because the ages are separated by groups (in this case, gender).b.This is stacked data because each row represents one person.c.This is unstacked data because the ages are separated by groups (in this case, gender).d.This is unstacked data because each row represents one person.

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1-2Chapter 1 Test A4.[Objective: Distinguish between numerical and categorical variables.] Determine which of thefollowing five variables are numerical and which are categorical.age, gender, weight, ethnicity, favorite math classa.All of the variables are categorical.b.All of the variables are numerical.c.Age, weight, and favorite math class are numerical variables. Gender and ethnicity arecategoricalvariables.d.Age and weight are numerical variables. Gender, ethnicity, and favorite math class arecategoricalvariables.5.[Objective: Distinguish between a population and a sample.] In a recent school poll, theadministrators asked if students were satisfied with the school’s course offerings.What is thepopulation of interest here?a.All students who are satisfied with the course offerings.b.All students who are not satisfied with the course offerings.c.All students who attend the school.d.All students who participated in the poll.Section 1.3 (Organizing Categorical Data)6.[Objective: Understand what types of variables are used in two-waytables.]A two-way table is useful for describing which types ofvariables?a.Two numerical variables.b.Two categorical variables.c.One numerical variable.d.One numerical variable and one categorical variable.7.[Objective: Find and use rates (including percentages).] In a study of 1200 adults, 480 out of the630 women in the study said they attended a state college oruniversity. What percent of thestudy’s participants were women?a. 40%b. 47.5%c. 52.5%d. 76.2%

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Chapter 1 Test A1-38.[Objective: Find and use rates (including percentages).] In a study of 1200 adults, 480 out of the630 women in the study said they attended a state college oruniversity. What percent of womenattended a state college or university?a. 40%b. 47.5%c. 52.5%d. 76.2%9.[Objective: Find and use rates (including percentages).] According to the following two-way table,what percent of people in the sample prefer dogs?MaleFemaleDog4025Cat2510a. 25%b. 35%c. 40%d. 65%10.[Objective: Understand when and why percents are more useful than counts for describing andcomparinggroups.] According to the following two-way table, why are percentages moreuseful than counts to compare petpreferences between males and females?MaleFemaleDog4025Cat2510a.There are more males than females in the sample.b.There are more people who prefer dogs than cats in the sample.c.You should only use counts in a two-way table.d.You should only use percentages in a two-way table.Section 1.4 (Collecting Data to Understand Causality)11.[Objective: Distinguish between observational studies and controlledexperiments.]Determine if the following scenario is an observational study or acontrolled experiment.A doctor is interested in determining whether a certain medication increases the risk ofhigh bloodpressure. He randomly selects 100 people for his study - 50 who will take themedication, and 50 whowill take a placebo. He checks the patients’ blood pressures weeklyfor six months.a.Observational studyb.Controlled experimentc.Neither

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1-4Chapter 1 Test A12.[Objective: Distinguish between observational studies and controlledexperiments.]Determine if the following scenario is an observational study or acontrolled experiment.A doctor is interested in determining whether a certain medication increases the risk ofhigh bloodpressure.He reviews his patients’ medical records and finds that a higherproportion of people whotake the medication are suffering from high blood pressure.a.Observational studyb.Controlled experimentc.Neither13.[Objective: Understand difference between treatment and outcome variables.] Researchersconducted an experiment to determine if children who participate in a new after-school tutoringprogram do better on state-mandated tests than children who do not attend the program. Whatare thetreatment and outcome variables?a.The treatment variable is participation in the after-school program. The outcome variable iswhetheror not a child attended.b.The treatment variable is participation in the after-school program. The outcome variable isthe testscore on the state-mandated test.c.The treatment variable is the state-mandated test. The outcome variable is theparticipation in theafter-school program.d.The treatment variable is the state-mandated test. The outcome variable is the test score onthe state-mandated test.14.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Researchers conducted a study and determined that studentswho participate in sports are happier thanstudents who do not. Can we conclude thatparticipating in sports makes students happier?a.Yes, this is an observational study and we can conclude causation.b.Yes, this is an experiment and we can conclude causation.c.No, this is an observational study and we cannot conclude causation.d.No, this is an experiment and we cannot conclude causation.

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Chapter 1 Test A1-515.[Objective: Suggest confounding variables that are likely to occur in some situations.] A gym isoffering a new 6-week weight loss exercise program for its members. Members who sign up forthe program are weighed and measured once a week for the duration of the program. The ownersof thegym want to know if the weight loss program actually helps people lose weight. Whatvariable could be apossible confounding factor in determining the cause of weight loss?a.The person’s commitment to the program.b.The person’s marital status.c.The person’s family structure.d.The person’s diet.16.[Objective: Determine when information is anecdotal.] In Los Angeles, juice cleansing is verypopular. Some people have claimed that the cleanses are beneficialfor weight loss, bodydetoxification, and treatment and prevention of illnesses. Can we conclude that juicecleansingcauses these health benefits?a.Yes, the claims are true stories, so we do have evidence of the health benefits.b.No, the claims are lies, so we do not have evidence of the health benefits.c.Yes, the claims are anecdotes and give us a good comparison group to find health differences.d.No, the claims are anecdotes and do not give us a true comparison group to find healthdifferences.17.[Objective: Understand different requirements for controlled experiments.]What does it mean foran experiment to be double-blinded?a.The researcher does not know which participants are in the treatment and control groups.b.The participants do not know who is in the treatment and control groups.c.Neither the researcher nor the participants know who is in the treatment and control groups.d.The researcher and the participants know which group they are in because it is unethical tokeep thisinformation from them.

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1-6Chapter 1 Test AUse the following information for questions (18) - (20):A group of 500 patients who suffer from hypothyroidism, a condition in which your thyroid does notproduceenough of certain hormones, were asked to participate in a study to determine theeffectiveness of a newmedication. The patients were randomly divided into two groups, one thatwas given the actual medication,and one that received a placebo pill. The results of the study arebelow.MedicationPlaceboSymptoms improved205140Symptoms did not659018.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] What percent of patients who took the medication hadimproved symptoms?a. 41%b. 54%c. 65.2%d. 75.9%19.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Was the new medication effective in treating hypothyroidism?a.Yes, a higher percent of patients who took the medication had improved symptoms than thepatientswho took the placebo.b.Yes, both groups had more patients with improved symptoms.c.No, the patients who took the placebo also had improved symptoms.d.No, this was not a controlled experiment.20.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Can we conclude that the improved symptoms were caused bythe new medication?a.Yes, this is a controlled experiment. Since a higher percent of patients who took themedication hadimproved symptoms, we can conclude causation.b.Yes, this is a controlled experiment. We can always conclude causation with a controlledexperiment.c.No, even though this is a controlled experiment, there was no difference between thetreatment andcontrol groups, so we cannot conclude causation.d.No, even though this is a controlled experiment, there might be a confounding factor since theplacebogroup had improved symptoms too.

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Chapter 1 Test A1-7Chapter 1 Test A - Answer Key1.B2.C3.C4.D5.C6.B7.C8.D9.D10.A11.B12.A13.B14.C15.D16.D17.C18.D19.A20.A

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Chapter 1 Test B1-1Chapter 1 Test B - Multiple ChoiceSection 1.1 (What are Data?)1.[Objective: Understand data.] Data can be defined asnumbers in context. Suppose you are given thefollowing set of numbers:18, 22, 22, 20, 19, 21What additional information would allow you to define these numbers as data?a.We need to know where these numbers were collected.b.We need to know who collected these numbers.c.Units of measurement. This could represent the ages of six high school students.d.Units of measurement. This could represent the ages of six college students.Section 1.2 (Classifying and Storing Data)2.[Objective: Understand methods for coding categorical variables.]According to the following datatable, which variable(s) is (are) categorical?AgeGenderShoe SizeEthnicity1811012307021062191111201103a.Genderb.Gender and ethnicityc.Gender, shoe size, and ethnicityd.None are categorical because there are only numbers in the table3.[Objective: Distinguish between stacked and unstacked data.]The following data table is organizedusing which method?GenderAgeMale35Female42Female33Male37Female39a.This is stacked data because the ages are separated by groups (in this case, gender).b.This is stacked data because each row represents one person.c.This is unstacked data because the ages are separated by groups (in this case, gender).d.This is unstacked data because each row represents one person.

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1-2Chapter 1 Test B4.[Objective: Distinguish between numerical and categorical variables.] Determine which of thefollowing five variables are numerical and which are categorical.age, gender, height, favorite candy, eye colora.Age, height, and favorite candy are numerical variables. Gender and ethnicity are categoricalvariables.b.Age and height are numerical variables. Gender, favorite candy, and eye color are categoricalvariables.c.All of the variables are categorical.d.All of the variables are numerical.5.[Objective: Distinguish between a population and a sample.] In a recent high school poll, theprincipal asked if students were satisfied with the amount of after-schoolactivities offered. What isthe population of interest here?a.All students who attend the school.b.All students who participated in the poll.c.All students who are satisfied with the amount of after-school activities that are offered.d.All students who are not satisfied with the amount of after-school activities that are offered.Section 1.3 Organizing Categorical Data6.[Objective: Understand what types of variables are used in two-way tables.]A two-way table couldbe used for which of the following pairs of variables?a.Age and heightb.Gender and agec.Gender and favorite classd.Age and favorite class7.[Objective: Find and use rates (including percentages).] In a study of 1350 elementary schoolchildren, 118 out of the 615 girls in the study said they want to be ateacher when they grow up.What percent of the study’s participants were boys?a. 19.2%b. 45.6%c. 54.4%d. 83.7%8.[Objective: Find and use rates (including percentages).] In a study of 1350 elementary schoolchildren, 118 out of the 615 girls in the study said they want to be ateacher when they grow up.What percent of girls want to be a teacher when they grow up?a. 8.7%b. 19.2%c. 45.6%d. 80.8%

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Chapter 1 Test B1-39.[Objective: Find and use rates (including percentages).] According to the following two-way table,what percent of people in the sample take naps?MaleFemaleNaps2530Does not nap3510a. 25%b. 35%c. 55%d. 60%10.[Objective: Find and use rates (including percentages).] According to the following two-way table,why are percentages more useful than counts to compare theamount of males and females who takenaps?MaleFemaleNaps2530Does not nap3510a.There are more males than females in the sample.b.There are more people who take naps than people who do not in the sample.c.You should only use counts in a two-way table.d.You should only use percentages in a two-way table.Section 1.4 Collecting Data to Understand Causality11.[Objective: Distinguish between observational studies and controlled experiments.]Determine if thefollowing scenario is an observational study or a controlled experiment.A doctor is interested in determining whether a certain medication reduces migraines. Sherandomlyselects 100 people for his study - 50 who will take the medication, and 50 whowill take a placebo.The patients are examined once a week for six weeks.a.Observational studyb.Controlled experimentc.Neither12.[Objective: Distinguish between observational studies and controlled experiments.]Determine if thefollowing scenario is an observational study or a controlled experiment.A doctor is interested in determining whether a certain medication reduces migraines. Shereviews herpatients’ medical records and finds that a higher proportion of people who takethe medication havefewer migraines than those who did not take the medication.a.Observational studyb.Controlled experimentc.Neither

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1-4Chapter 1 Test B13.[Objective: Understand difference between treatment and outcome variables.] Researchers conductedan experiment to determine if riding a bike to school improves attention span. Whatare the treatmentand outcome variables?a.The treatment variable is riding a bike to school. The outcome variable is whether or not thechild rodea bike to school.b.The treatment variable is riding a bike to school. The outcome variable is the child’s attentionspan.c.The treatment variable is attention span. The outcome variable is whether or not the child rodea biketo school.d.The treatment variable is attention span. The outcome variable is the child’s attention span score.14.[Objective: Understand when it is possible to infer a cause-and-effect relationship from a researchstudyand when it is not.] Researchers conducted a study and determined that students whocarpool have less friends than studentswho ride the bus to school. Can we conclude that carpoolingcauses students to have less friends?a.Yes, this is an observational study and we can conclude causation.b.Yes, this is an experiment and we can conclude causation.c.No, this is an observational study and we cannot conclude causation.d.No, this is an experiment and we cannot conclude causation.15.[Objective: Suggest confounding variables that are likely to occur in some situations.] A gym isoffering a new 6-week diet plan for its members. Members who sign up for the program areweighed and measured once a week for the duration of the program. The owners of the gym want toknowif the diet plan actually helps people lose weight. What variable could be a possibleconfounding factor indetermining the cause of weight loss?a.The person’s education level.b.The person’s marital status.c.The person’s social life.d.The person’s exercise routine.16.[Objective: Determine when information is anecdotal.] Coconut oil has become quite popular inrecent years. People who use coconut oil claim it helps with haircare, skin care, stress relief, weightloss, and a boosted immune system. Can we conclude that the use ofcoconut oil causes these healthbenefits?a.Yes, the claims are anecdotes and give us a good comparison group to find health differences.b.No, the claims are anecdotes and do not give us a true comparison group to find healthdifferences.c.Yes, the claims are true stories, so we do have evidence of the health benefits.d.No, the claims are lies, so we do not have evidence of the health benefits.

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Chapter 1 Test B1-517.[Objective: Understand different requirements for controlled experiments.]What does it mean for anexperiment to be random?a.Assignment into the control and treatment groups is determined by chance.b.Assignment into the control and treatment groups is determined by the researcher.c.Assignment into the control and treatment groups is determined by the participants.d.Assignment into the control and treatment groups is determined by a person who is not involvedin theresearch.Use the following information for questions (18) - (20):A group of 500 patients who suffer from skin cancer were asked to participate in a study todetermine theeffectiveness of a new medication. The patients were randomly divided into twogroups, one that was giventhe actual medication, and one that received a placebo pill. A goodoutcome was defined as the cancer beingin remission after 6 months of treatment. The results of thestudy are below.MedicationPlaceboRemission160130Not in8013018.[Objective: Understand when it is possible to infer a cause-and-effect relationship from a researchstudyand when it is not.] Approximately what percent of patients who took the medication hadcancer remission?a. 48%b. 50%c. 58%d. 67%19.[Objective: Understand when it is possible to infer a cause-and-effect relationship from a researchstudyand when it is not.] Was the new medication effective for cancer remission?a.Yes, a higher percent of patients who took the medication had cancer remissions than thepatients whotook the placebo.b.Yes, both groups had more patients with cancer remissions.c.No, the patients who took the placebo also had cancer remissions.d.No, this was not a controlled experiment.

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1-6Chapter 1 Test B20.[Objective: Understand when it is possible to infer a cause-and-effect relationship from a researchstudyand when it is not.] Can we conclude that the cancer remissions were caused by the newmedication?a.Yes, this is a controlled experiment. Since a higher percent of patients who took themedication hadcancer remissions, we can conclude causation.b.Yes, this is a controlled experiment. We can always conclude causation with a controlledexperiment.c.No, even though this is a controlled experiment, there was no difference between thetreatment andcontrol groups, so we cannot conclude causation.d.No, even though this is a controlled experiment, there might be a confounding factor since theplacebogroup had cancer remissions too.

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Chapter 1 Test B1-7Chapter 1 Test B - Answer Key1.D2.B3.B4.B5.A6.C7.C8.B9.C10.A11.B12.A13.B14.C15.D16.B17.A18.D19.A20.A

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Chapter 1 Test C1-1Chapter 1 Test C - Short AnswerSection 1.1 (What are Data?)1.[Objective: Understand data.] Give an example of how data could be collected about you on a dailybasis.Section 1.2 (Classifying and Storing Data)2.[Objective: Understand methods for coding categorical variables.] In the following table, gender isa categorical variable. Give one possible way the variable could have beencoded.AgeGenderShoe Size181102307210619111201103.[Objective: Distinguish between stacked and unstacked data.] Determine whether the followingdata table is stacked or unstacked and explain your reasoning.AgeSchool Year18Freshman20Sophomore19Sophomore21Junior21Senior4.[Objective: Distinguish between numerical and categorical variables.]Give an example of onecategorical variable and one numerical variable.5.[Objective: Distinguish between a population and a sample.] In a recent survey at UCLA, someincoming freshmen students were asked if they planned to take more thanone math class before theygraduated. What is the population of interest here and what is the sample?Section 1.3 (Organizing Categorical Data)6.[Objective: Understand what types of variables are used in two-way tables.]What types of variablesare represented in a two-way table? Give an example.7.[Objective: Find and use rates (including percentages).] In a recent study of 1200 adult smokers,125 out of the 560 males in the study said they were interested injoining a help group to quitsmoking. What percent of the study’s participants were female?

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1-2Chapter 1 Test C8.[Objective: Find and use rates (including percentages).] In a recent study of 1200 adult smokers,125 out of the 560 males in the study said they were interested injoining a help group to quitsmoking. What percent of males are interested in joining this group?9.[Objective: Find and use rates (including percentages).] According to the following two-way table,what percent of people in the sample eat breakfast?MaleFemaleEat breakfast3540Skips breakfast20510.[Objective: Find and use rates (including percentages).] According to the following two-way table,why are percentages more useful than counts to compare theamount of males and females whoeat breakfast?MaleFemaleEat breakfast3540Skips breakfast205Section 1.4 (Collecting Data to Understand Causality)11.[Objective: Distinguish between observational studies and controlled experiments.] Determine ifthe following scenario is an observational study or a controlled experiment and explain yourreasoning.A school teacher is interested in determining whether students who take multiple choicetests do betterthan students who take true/false tests. She has been giving multiplechoice tests since she startedteaching and is wondering if she should change her testingmethod. She randomly assigns half of herstudents to take a multiple choice test aboutgrammar rules, and the other half to take a true/false testabout grammar rules. Shecompares the test scores of the students in each group.12.[Objective: Distinguish between observational studies and controlled experiments.] Determine ifthe following scenario is an observational study or a controlled experiment and explain yourreasoning.A doctor is interested in determining whether a certain medication is effective at treatingabdominalpain.He reviews his patients’ medical records and finds that a higherproportion of people who tookthe medication fewer abdominal pain symptoms than thosewho did not take the medication.13.[Objective: Understand difference between treatment and outcome variables.] Researchersconducted an experiment to determine if having adog dayon college campuses during finalexamweek lowers students’ stress levels. Adog dayis when dogs from a local animal shelter arebroughtonto campus for students to play and interact with. What are the treatment and outcomevariables for thisexperiment?

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Chapter 1 Test C1-314.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Researchers conducted a study and determined that coworkerswho socialize outside of work are more productive than coworkers who do not. Can we concludethat socializing outside of work causes coworkers tobe more productive? Explain your reasoning.15.[Objective: Suggest confounding variables that are likely to occur in some situations.] A college isoffering a new free tutoring program for students in an introductory statistics class. The schoolwants to know if this new program improves students’ test scores on their midterms and finalexams. Whatvariable could be a possible confounding factor in determining why students’ scoresimproved or not?16.[Objective: Determine when information is anecdotal.] Give an example of how anecdotal evidencecan be used to persuade consumers to purchase a product.17.[Objective: Understand different requirements for controlled experiments.] What is the differencebetween a blind and a double blind study? Which is most ideal?Use the following information for questions (18) - (20):A group of 500 patients who suffer from severe migraines were asked to participate in a study todetermine the effectiveness of a new medication. The patients were randomly divided into twogroups, one that wasgiven the actual medication, and one that received a placebo pill. A goodoutcome was defined as a reductionin the number of migraines during a month’s time. The results ofthe study are below.MedicationPlaceboMigraines reduced18570Migraines did not9015518.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Approximately what percent of patients who took themedication had a reduction in the amount of migraines?19.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Was the new medication effective for reducing migraines?Explain your reasoning and include any calculations.20.[Objective: Understand when it is possible to infer a cause-and-effect relationship from aresearch studyand when it is not.] Can we conclude that the reduction of migraines was causedby the new medication? Explain your reasoning.

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1-4Chapter 1 Test CChapter 1 Test C – Answer Key1.Answers will vary.Examples might include:Facebook postings, Twitter tweets, Instagramphotos, emailssent/received, credit/debit card swipes, GPS, text messaging, etc.2.2 possible ways to code: 0 - Male, 1 - Female; OR 0 - Female, 1 - Male3.This is stacked data because each row represents one person.4.Answers will vary. Examples might include: categorical - gender, favorite candy, year in school,favoritecolor, etc.; numerical - age, height, weight, speed, etc.5.The population is the entire freshman class at UCLA. The sample includes the particularfreshmen whoparticipated in the survey.6.Two categorical variables. Answers will vary. Examples might include: gender & favorite color,gender &year in school, year in school & favorite animal, etc.7.6400.53353.3%12008.1250.22322.3%5609.750.7575%10010.The group sizes are different. There are 55 males, but only 45 females.11.This is a controlled experiment because the students are randomly assigned to the treatment group(true/falsetest) and the control group (multiple choice test).12.This is an observational study because the doctor did not randomly assign patients into groups.Instead, hesimply looked at medical files.13.Treatment variable - whether or not a campus had adog day. Outcome variable - students’stress levelsduring final exams.14.No, this is an observational study and we cannot conclude causation.15.Answers will vary. Examples might include: a student’s access to other help/tutoring programs, astudent’smajor on campus (e.g. a mathematics major versus a history major), a student’s studyskills prior to theprogram, etc.16.Answers will vary. Examples might include: (1) a pregnancy blog references a few individualwomen’sexperiences with cocoa butter lotion and its reduction of stretch marks, (2) a localhealth store includesquotes from 5 customers on an advertisement that claims coconut oilconsumption can reduce stress andimprove health, (3) a commercial for skincare productsinterviews a small group of people that claim theproduct has cured their acne, etc.

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Chapter 1 Test C1-517.In a blind study, the participants do not know which group they have been assigned to. Forexample, in amedical experiment, the patients do not know if they are receiving actualmedication or just a placebo. Ina double blind study, neither the researchers, nor theparticipants know which group the participants havebeen assigned to. A double blind study isbetter than a blind study.18.1851850.672767.3%1859027519.Yes, a higher percent of patients who took the medication had fewer migraines(18567.3%275) than the patients who took the placebo (7031.1%225).20.Yes, this is a controlled experiment. Since a higher percent of patients who took the medicationhad fewermigraines, we can conclude causation.

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Chapter 2 Test A2-1Chapter 2 Test A - Multiple ChoiceSection 2.1 (Visualizing Variation in Numerical Data)1.[Objective: Understand the difference between how observations are recorded in dotplots,histograms, andstemplots.] How are individual observations recorded in a dotplot, a histogram,and a stemplot?a.A dotplot displays the actual values of observations. A histogram displays a dot for everyobservation.A stemplot uses bars to display intervals of observations.b.A dotplot displays a dot for every observation. A histogram uses bars to display intervals ofobservations. A stemplot displays the actual values of observations.c.A dotplot displays the actual values of observations. A histogram uses bars to displayintervals ofobservations. A stemplot displays a dot for every observation.d.A dotplot uses bars to display intervals of observations. A histogram displays a dot for everyobservation. A stemplot displays the actual values of observations.2.[Objective: Understand the difference between frequencies and relative frequencies.]What is thedifference between a histogram and a relative frequency histogram?a.A histogram uses numbers to record how many observations are in a data set, and a relativehistogramuses categories.b.A histogram uses categories to record how many observations are in a data set, and a relativehistogramuses counts.c.A histogram uses counts to record how many observations are in a data set, and a relativehistogramuses proportions.d.A histogram uses proportions to record how many observations are in a data set, and arelative histogram uses counts.

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2-2Chapter 2 Test A3.[Objective: Determine significance of bin width in a histogram.] In the following histogram, whatcan you conclude about the bin width?a.The bin width is too small. We are given too much detail.b.The bin width is too large. We are given too much detail.c.The bin width is too small. We are hiding details of the distribution.d.The bin width is too large. We are hiding details of the distribution.4.[Objective: Understand that a distribution of a sample of data can be displayed multiple ways.]Which histogram represents the same data as the dotplot shown below?

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Chapter 2 Test A2-3Section 2.2 (Summarizing Important Features of a Numerical Distribution)5.[Objective: Know what to pay attention to in distributions of numerical data.] When examiningdistributions of numerical data, what three components should you look for?a.Symmetry, center, and spreadb.Symmetry, skewness, and spreadc.Shape, symmetry, and spreadd.Shape, center, and spread6.[Objective: Understand modality in distributions.] Which of the following would likely show abimodal distribution in a histogram?a.The heights of all students in a high school band.b.The ages of students who attend a 4-year university.c.The number of hours preschoolers plays outside.d.The final exam grades for an introductory statistics course.For questions (7) - (9), match one of the histograms below with its appropriate description.7.[Objective: Recognize the shape of a distribution.] The distribution of scores on an easy test isdisplayed in histogram.8.[Objective: Recognize the shape of a distribution.] The distribution of household income in a largecity is displayed in histogram.9.[Objective: Recognize the shape of a distribution.] The distribution of female heights is displayed inhistogram.

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2-4Chapter 2 Test A10.[Objective: Understand how to find typical values from a histogram.] The following histogramrepresents audience movie ratings (on a scale of 1-100) of 489 movies. What isthetypicalmovierating given by audiences according to this distribution?a.The typical value is about 40.b.The typical value is about 50.c.The typical value is about 60.d.The typical value is about 70.11.[Objective: Determine differences in variability.] Order the following histograms from least to mostvariability.a.(i), (ii), (iii)b.(ii), (i), (iii)c.(ii), (iii), (i)d.(iii), (i), (ii)

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Chapter 2 Test A2-512.[Objective: Interpreting typical values of bimodal distributions.]What is the typical value for thehistogram shown below?a.The typical value is 40 because it is the center of the distribution.b.The typical value is 40 because it is the average of 20 and 60.c.Since the data are bimodal, a typical value cannot be found.d.Since the data are bimodal, there are two typical values - one is about 20 and the other is about60.Section 2.3 (Visualizing Variation in Categorical Variables)13.[Objective: Understand differences between bar charts and histograms.]What is thedifference between a bar chart and a histogram?a.They can both be used to represent numerical data.b.They can both be used to represent categorical data.c.A bar chart represents numerical data and a histogram represents categorical data.d.A bar chart represents categorical data and a histogram represents numerical data.

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2-6Chapter 2 Test A14.[Objective: Interpreting bar charts.] Which statement below is NOT supported by the following barchart?a.More females wear sunscreen than males.b.Very few people, in general, always wear sunscreen.c.More males wear sunscreen than females.d.About 50% of males never wear sunscreen.Section 2.4 (Summarizing Categorical Distributions)15.[Objective: Determine the variability of categorical data from a bar chart.] The bar charts belowdepict the veteran statuses of Americans, separated by gender. Which bar chart hasmorevariability in veteran status? Why?a.The female bar chart shows more variability because many of the observations fall into onecategory(“Non-Veteran”).b.The female bar chart shows more variability because there are more observations in thedifferentcategories than there are for males.c.The male bar chart shows more variability because many of the observations fall into onecategory (“Non-Veteran”).d.The male bar chart shows more variability because there are more observations in thedifferent categories than there are for females.

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Chapter 2 Test A2-716.[Objective: Understand the termmodewhen describing categorical variables.]What does it meanto find themodeof a bar chart?a.You cannot find a mode for categorical data. Modes are only used with numerical data.b.The mode can be found by finding the bar, or category, with the most observations.c.The mode can be found by adding up the total number of categories.d.The mode can be found by adding up the total number of observations and dividing by thenumber ofcategories.Section 2.5 (Interpreting Graphs)Use the following information to answer questions (17) - (18):A large state university conducted a survey among their students and received 300 responses.The surveyasked the students to provide the following information:*Age*Year in School (Freshman, Sophomore, Junior, Senior)*Gender*GPA17.[Objective: Determine appropriate graph based on variable type.]What type of graph would youuse to describe the variable Age?a.A histogram because Age is a numerical variable.b.A histogram because Age is a categorical variable.c.A bar chart because Age is a numerical variable.d.A bar chart because Age is a categorical variable.18.[Objective: Determine appropriate graph based on variable type.] What type of graph would you useto describe the variables Gender and Year in School?a.A side-by-side histogram should be used since these are two numerical variables.b.A side-by-side histogram should be used since these are two categorical variables.c.A side-by-side bar chart should be used since these are two numerical variables.d.A side-by-side bar chart should be used since these are two categorical variables.

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2-8Chapter 2 Test AA word cloud was created using the first chapter of Lewis Carroll’s Alice’s Adventures in Wonderland.(Note that filler words such as “the,” “a/an,” and “and” were excluded from the plot.)Use the word cloud to answer questions (19) - (20).19.[Objective: Interpreting word clouds.] According to the word cloud, what is the most commonword in the first chapter of Alice’s Adventures in Wonderland? Why?a.The most common word is “alice” because it is the largest in size.b.The most common word is “alice” because she is a main character in the story.c.The most common word is “marked” because it appears at the top of the cloud.d.The most common word is “garden” because it appears in the middle of the cloud.20.[Objective: Pitfalls of using word clouds.] What information is NOT explicitly portrayed in theword cloud?a.The words that occur most frequently in the chapter.b.The specific word that occurs most often.c.The number of times each word occurs.

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Chapter 2 Test A2-9Chapter 2 Test A - Answer Key1.B2.C3.A4.A5.D6.A7.A8.C9.B10.C11.D12.D13.D14.C15.D16.B17.A18.D19.A20.C

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Chapter 2 Test B2-1Chapter 2 Test B - Multiple ChoiceSection 2.1 (Visualizing Variation in Numerical Data)1.[Objective: Determine significance of bin width in a histogram.] In the following histogram, whatcan you conclude about the bin width?a.The bin width is too small. We are given too much detail.b.The bin width is too large. We are given too much detail.c.The bin width is too small. We are hiding details of the distribution.d.The bin width is too large. We are hiding details of the distribution.2.[Objective: Understand the difference between frequencies and relative frequencies in a histogram.]The two histograms below display the exact same data. How do the plots differ?a.Histogram (i) uses frequencies to simply count the number of observations at a given value.Histogram (ii) uses relative frequencies to show the proportion of observations at a given value.b.Histogram (i) uses relative frequencies to show the proportion of observations at a givenvalue. Histogram (ii) uses frequencies to simply count the number of observations at a givenvalue.c.Histograms (i) and (ii) are exactly the same; there are no differences between the plots.d.Histograms (i) and (ii) do not display the same data because the valueslisted on they-axis do notmatch.

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2-2Chapter 2 Test B3.[Objective: Understand the difference between how observations are recorded in dotplots andstemplots.]How are individual observations recorded in a dotplot versus a stemplot?a.A dotplot displays the actual values of observations.A stemplot uses bars todisplay intervals ofobservations.b.A dotplot displays the actual values of observations. A stemplot displays a dot for everyobservation.c.A dotplot displays a dot for every observation. A stemplot displays the actual values ofobservations.d.A dotplot displays a dot for every observation. A stemplot uses bars to displayintervals of observations.4.[Objective: Understand that a distribution of a sample of data can be displayed multiple ways.]Which dotplot represents the same data as the histogram shown below?

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