W3 - Chapter 3 - DN Flashcards
1
Q
arithmetic mean
A
- a measure of central tendency
- derived by calculating an average of all scores in a distribution
- also called the mean
p. 89
2
Q
average deviation
A
- 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
3
Q
bar graph
A
- 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
4
Q
bimodal distribution
A
- 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
5
Q
bivariate distribution
A
- 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
6
Q
coefficient of correlation
A
- 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
7
Q
coefficient of determination
A
- 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
8
Q
correlation
A
- an expression of the degree and direction of relationship (correspondence) between two variables
- where each variable is continuous in nature
p. 106-116
9
Q
curvilinearity
A
- the degree to which a graph or scatterplot is characterized by curvature
p. 111
10
Q
distribution
A
- in a psychometric context
- a set of test scores arrayed for recording or study
p.83
11
Q
dynamometer
A
- an instrument used to measure the strength of hand grip
p. 82
12
Q
effect size
A
- 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
13
Q
error
A
- 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
14
Q
frequency distribution
A
- a tabular listing of
- scores
- along with the number of times each score occurred
p.83-85
15
Q
frequency polygon
A
- 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
16
Q
graph
A
- a diagram or chart
- composed of lines, points, bars, or other symbols that describe and illustrate data
p.85
17
Q
grouped frequency distribution
A
- a tabular summary of test scores
- the test scores are grouped by intervals
- also referred to as class intervals
p. 84-85
18
Q
histogram
A
- 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
19
Q
interquartile range
A
- 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
20
Q
interval scale
A
- 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
21
Q
kurtosis
A
- an indication of the nature of the steepness of the centre of the distribution
- i.e., peaked vs flat
p.97-98
22
Q
leptokurtic
A
- a description of the kurtosis of a distribution that is relatively peaked at its centre
23
Q
linear transformation
A
- in psychometrics
- a process of changing a score such that
- the new score has a direct numerical relationship to the original score
- the magnitude of the difference between the new score & other scores on the scale parallels the magnitude of differences on the scale from which it was derived
- contrast with nonlinear transformation
p. 104
24
Q
mean
A
- a measure of central tendency
- derived by calculating an average of all scores in a distribution
- also called an arithmetic mean
p. 89