Chapter 4

Question 1

measures of variability

Answer 1

Numbers that describe diversity or variability in the distribution of a variable.

Question 2

index of qualitative variation (IQV)

Answer 2

A measure of variability for nominal variables. It is based on the ratio of the total number of differences in the distribution to the maximum number of possible differences within the same distribution.

Question 3

range

Answer 3

A measure of variation for interval-ratio variables. It is the difference between the highest (maximum) and the lowest (minimum) scores in the distribution.

Question 4

interquartile range (IQR)

Answer 4

The width of the middle 50% of the distribution. It is defined as the difference between the lower and upper quartiles (Q1 and Q3). IQR can be calculated for interval-ratio and ordinal data.

Question 5

variance

Answer 5

A measure of variation for interval-ratio and ordinal variables; it is the average of the squared deviations from the mean.

Question 6

standard deviation

Answer 6

A measure of variation for interval-ratio and ordinal variables; it is equal to the square root of the variance.