Statisticsacademic

A 9-year-old girl conducted a science fair experiment to test whether professional touch therapists could sense her energy field. She flipped a coin to select either her right hand or left hand and asked the therapists to identify the chosen hand by placing their hand just below hers, without seeing it and without touching it. Among 282 trials, the touch therapists were correct 117 times. Use a 0.10 significance level to test the claim that touch therapists use a method equivalent to random guesses. Do the results suggest that touch therapists are effective? What is the test statistic for this hypothesis test? Round your answer to two decimal places.

An automobile manufacturer sold 30,000 new cars, one to each of 30,000 customers, in a certain year. The manufacturer was interested in investigating the proportion of the new cars that experienced a mechanical problem within the first 5,000 miles driven. A list of the names and addresses of all customers who bought the new cars is available. Each customer from a simple random sample of 1,000 customers who bought one of the new cars was asked whether they experienced any mechanical problems within the first 5,000 miles driven. 400 customers from the sample reported a problem. Of the 400 customers who reported a problem, 140 customers, or 35%, reported a problem specifically with the power door locks. Explain why 0.35 should not be used to estimate the population proportion of the 30,000 new cars sold that experienced a problem with the power door locks within the first 5,000 miles driven.

Why is replication important to consider when designing an experiment? Replication provides the baseline condition for the independent (treatment) variable. Replication increases the chances that your results apply only to specific cases. Replication is necessary to introduce systematic variation into an experiment. Replication reduces the chances that a rare result leads you to an erroneous conclusion.

For a person with an IQ of 145, his or her score would be _____ standard deviations above the normative mean. Possible answers: A. 1 B. 2 C. 3 D. 4

How do you calculate relative frequency?

What is the mean absolute deviation of the following set: 3, 1, 5, 5, 2, 3, 2, 3, 4, 2?

What is the interquartile range of the data set: 5, 6, 7, 8, 9, 10, 11?

Which of the following is an example of stratified sampling? (a) A sample of 351 people called a radio show to express their opinions about the verdict in the Michael Jackson trial. (b) In order to assess students' satisfaction with the food establishment on campus, the first 50 students that come out of the student center were interviewed. (c) A poll asked a random sample of 1,112 adults whether they believe that the use of marijuana for medical reasons should be legalized. (d) A health educator wanted to study the sleeping habits of the undergraduate students in her university. For her study, the researcher chose a simple random sample of size 150 from each of the classes (150 freshmen, 150 sophomores, 150 juniors, and 150 seniors), for a total of 600 sampled students. (e) The human resources department of a large bank wanted to assess the job satisfaction of the bank's workers. The department chose four of the bank's branches at random, and used all of the workers in those four branches as the subjects for the study.