Psychological - W3 - Chapter 3 - DN Part 1

a measure of central tendency

derived by calculating an average of all scores in a distribution

also called the mean

p. 89

a measure of variability

derived by

summing the absolute value of all the scores in a distribution and

dividing by the total number of scores

p. 94

a graphic illustration of data

numbers indicative of frequency are set on the vertical axis

categories are set on the horizontal axis

the rectangle bars that describe the data are typically noncontigous

p. 85

a distribution where the central tendency consists of

two scores

occurring an equal number of times

and are the most frequently occurring scores in the distribution

p. 91

a graphic representation of correlation

accomplished by the simple graphing of the coordinate points for values of

the X-variable and

the Y-variable

also known as a

scatterplot

scatter diagram

scattergram

p. 111

symbolised by r

the correlation coefficient is an index of the strength of the linear relationship between two continous variables

expressed as a number

can range from -1 to +1

most frequently used statistic to calculate is the Pearson r

p. 106

a value indicating how much variance is shared by two variables

this value is obtained by

squaring the obtained correlation coefficient

multiplying by 100 and

expressing the result as a percentage

this indicates the amount of variance accounted for by the correlation coefficient

i.e., “total variance explained”

p.109

an expression of the degree and direction of relationship (correspondence) between two variables

where each variable is continuous in nature

p. 106-116

the degree to which a graph or scatterplot is characterized by curvature

p. 111

in a psychometric context

a set of test scores arrayed for recording or study

p.83

an instrument used to measure the strength of hand grip

p. 82

a statistic used to express

the strength of a relationship or

the magnitude of the differences in data

in meta-analysis - this statistic is most typically a correlation coefficient

p. 115

all of the factors (other than what a test purports to measure) that contribute to scores on a test

error is a variable that exists on all testing and assessment

p. 78-79

a tabular listing of

scores

along with the number of times each score occurred

p.83-85

a graphic illustration of data

frequency numbers set on the vertical axis

test scores or categories are set on the horizontal axis

data is described by a continous line connecting all of the points where the test scores or categories meet frequencies

p. 85,86

a diagram or chart

composed of lines, points, bars, or other symbols that describe and illustrate data

p.85

a tabular summary of test scores

the test scores are grouped by intervals

also referred to as class intervals

p. 84-85

a graph with vertical lines drawn at the true limits of each test score (or class interval)

these lines form a contigous rectangle

p. 85,86

an ordinal statistic of variability

equal to the difference between the third & first quartile points in a distribution that has been divided into quartiles

p. 94

a system of measurement

all items are rank-ordered into equal intervals

every unit on the scale is equal to every other

there is no absolute zero point

this precludes mathematical operations on the data

p.81