Data Analysis with Microsoft Excel: Updated for Office 2007

Chapter 9 Multiple Regression 383

On the basis of the descriptive statistics, you can conclude that the female

faculty are paid, on average, $3,063.64 less than what would be expected

for equally qualifi ed male faculty members (as quantifi ed by the predictor

variables). The largest discrepancy is for a female faculty member who is

paid $8,825 less than expected (cell B9). Of those with salaries greater than

predicted, there is a female faculty member who is paid $2,090 more than

expected (cell B10).

To understand the salary defi cit better, you can plot residuals against the

relevant predictor variables. Start by plotting the female salary residuals

versus age when hired. (You could plot residuals versus years employed,

but you would see no particular trend in the pattern of the residuals.)

To plot the residuals against Age Hired:

1 Click the Female Faculty sheet tab to return to the data worksheet.

2 Using either the StatPlus Fast Scatterplot command or the Scatter-

chart button on the Insert tab of the Excel ribbon, create a scatter

plot of Residuals (H1:H38) versus Age Hired (D1:D38).

Figure 9-19
Descriptive
statistics of
the residuals
for female
faculty