Measure of Variability

Question 1

Range

Answer 1

A measure of variability that measures the total spread in the data. Can be influenced easily by extreme scores.
Range = highest score-lowest score.
Used for nominal and ordinal data

Question 2

Average Deviation

Answer 2

A measure of how much each score deviates from the mean.
sum of absolute value of deviations divided by N.

Question 3

Variance

Answer 3

A measure of the sum of squared deviations from the mean divided by n.

Question 4

Standard Deviation

Answer 4

A measure of variability for scores about the mean. A measure of deviations of all the scores from the mean, expressed as a single number.
It is a method of specifying the percentage of scores that fall within certain limits around the mean.
Different formula for samples and populations.
Used for interval and ratio data
Range about the mean over which 68% of scores from a sample fall.