A telemarketing company wants to compare the effectiveness of five of its employees by looking at the percentage of survey questions completed.Data from four past surveys are randomly chosen for each of the employees,and the percentage of completed questions is calculated.The box plots for the five employees are shown below.
A)Yes,the widths of all the boxes are the same.
B)No,the data need to be log-transformed before conducting the ANOVA.
C)Yes,the spreads of the five box plots appear similar enough to satisfy the assumption.
D)No,the centre line for employee four is lower than all of the others
E)No,the data probably need to be re-expressed before conducting the ANOVA.

Question

A telemarketing company wants to compare the effectiveness of five of its employees by looking at the percentage of survey questions completed.Data from four past surveys are randomly chosen for each of the employees,and the percentage of completed questions is calculated.The box plots for the five employees are shown below. 
A)Yes,the widths of all the boxes are the same. 
B)No,the data need to be log-transformed before conducting the ANOVA. 
C)Yes,the spreads of the five box plots appear similar enough to satisfy the assumption. 
D)No,the centre line for employee four is lower than all of the others 
E)No,the data probably need to be re-expressed before conducting the ANOVA.

Quizplus · Accepted Answer

The assumption for ANOVA is that the populations should have equal variances. One way to check this assumption is to look at the spreads of the box plots. Since the spreads of the five box plots appear similar enough, we can conclude that the assumption has been met. A is incorrect as the boxes may not look identical but they all appear to have similar spreading. B and E are incorrect as there is no indication that the data need to be transformed or re-expressed. D is incorrect as the center line for employee four is not relevant to the assumption of ANOVA.

A Telemarketing Company Wants to Compare the Effectiveness of Five