Data Analysis with Microsoft Excel: Updated for Office 2007

384 Statistical Methods

3 Give a chart title of Residuals vs. Age Hired, and label the x axis

Age Hired and the y axis Residuals. Save the chart in a new chart

sheet named Female Resid vs. Age Hired.

4 Change the scale of the x axis from 0–60 to 20–50. Your chart should

look like Figure 9-20.

Figure 9-20

Scatter plot

of residuals

versus Age

Hired for

female

faculty

There seems to be a downward trend to the scatterplot, indicating that the

greater discrepancies in salaries occur for older female faculty. Add a linear

regression line to the plot, regressing residuals versus age when hired.

To add a linear regression line to the plot:

1 Right-click the data series (any one of the data points in Figure 9-20),

and click Add Trendline in the shortcut menu.

2 Verify that the Linear Trend/Regression Type option is selected, and

then click Close. Your plot should now look like Figure 9-21.