A qualitative variable with three classes (X, Y, and Z) is measured for each of 20 units randomly sampled from a target population. The data (observed class for each unit)

are as follows:

Y X X Z X Y Y Y X X Z X Y Y X Z Y Y Y X

a. Compute the frequency for each of the three classes.

b. Compute the relative frequency for each of the three classes.

c. Display the results from part a in a frequency bar graph.

d. Display the results from part b in a pie chart.