The manager of a large industrial plant is interested in investigating whether age has an effect on the leadership ability of employees. 66 employees were randomly selected, divided into two groups according to their age; either under 40 years old or at least 40 years old and given a leadership exam. The employee's score in the leadership exam was recorded. The data are displayed below:
(a) Use SPSS to draw the appropriate box plot(s) for this data set. (You should consider the design of this study to ensure the relevant plot(s) is drawn.) Comment on any features in the plot(s).
(b) Is there a difference in the underlying mean leadership scores for employees aged under 40 and those at least 40 years old? Use SPSS to investigate this question. Interpret your results.