Refer to the British Journal of Music Education (Mar. 2014) study of music performance anxiety, Exercise 2.62 (p. 61). Scores (measured in points) on the Performance Anxiety Inventory (PAI) scale for participants in eight different studies are reproduced in the table.

a. Find the variance of the sample PAI scores. Give the units of measurement for the variance.
b. Find the standard deviation of the sample PAI scores. Give the units of measurement for the standard deviation.