Data Analysis with Microsoft Excel: Updated for Office 2007

252 Fundamentals of Statistics

The bottom line is that if there is some question about whether to use a

parametric or a nonparametric test, do the analysis both ways.

Excel does not include any nonparametric tests, but you can use StatPlus

to generate test results using the Wilcoxon Signed Rank test. Apply this test

now to the work force data. Your hypotheses are

H 0 : Median population difference 50

Ha: Median population difference 20

To analyze the difference data using the Wilcoxon Signed Rank test:

1 Click One Sample Tests from the StatPlus menu and then click

1 Sample Wilcoxon Sign Rank test.

2 Verify that the 1-sample W-test option button is selected.

3 Click the Input button, select Diff from the list of range names, and

click the OK button.

4 Click the Output button and select the New Worksheet option button.

Enter W-test for the new worksheet name and click the OK button.

5 Click the OK button to generate the output from the Wilcoxon Signed

Rank test. See Figure 6-16.

median

difference

Figure 6-16
Wilcoxon
signed rank
analysis of the
Diff data

95% confidence

interval

parameter values of the

hypothesis test

number of values value

<, =, and > 0

p

The results of our analysis using the Wilcoxon Signed Rank test are simi-

lar to the results with the t test. We still reject the null hypothesis, this time

with a stronger p value of 0.009. The 95% confi dence interval is pretty close

to what we calculated before, (0.005, 0.060). Moreover, we learn that the

number of cities whose percentage of women in the workforce increased

from 1968 to 1972 was 13 and that only 2 cities showed a decrease in