Descriptive Statistics (Measures of Variability)

Question 1

provides a quantitative measure of the difference between scores in a distribution and describes the degree to which the scores are spread out or clustered together.

Answer 1

Variability

Question 2

What is the Purpose of Measuring Variability

Answer 2

1. Variability describes the distribution.
2. Variability measures how well an individual score (or group of scores) represents the entire distribution.

Question 3

distance covered by the scores in a distribution, from the smallest score to the largest score

difference between the largest score and smallest score

Answer 3

Range

Question 4

measure of how spread out a set of scores are; average of the squared deviations from the mean

Answer 4

Variance

Question 5

the difference between a score and the mean

Answer 5

Deviation or Deviation Score

Question 6

square root of the average of the squared deviations from the mean; the most common descriptive statistics for variation;
approximately the average amount that scores in a distribution vary from the mean

Answer 6

Standard Deviation

Question 7

if the average value of the statistic either underestimates or overestimates the corresponding population parameter

Answer 7

Biased Statistics

Question 8

if the average value of the statistic is unequal to the population parameter

Answer 8

Unbiased Statistics

Question 9

• Adding a constant to each score does not change the standard deviation
• Multiplying each score by a constant causes the standard deviation to be multiplied by the same constant

Answer 9

Transforming a Scale