How to Do the Calculations for Chi-Square Problems Using Statlet

You work in a hospital that has pretty strict enforcement of immunization schedules for employees. However, most of the physicians practicing at your hospital are not employees of the hospital. You suspect that the proportion of physicians current on their Tuberculosis immunizations differs from that of employees. You sample 26 employees and 18 physicians and discover that 5 of those employees and 18 of those physicians are not up to schedule on their TB immunizations.

1. When you start Statlets, the following spreadsheet should appear. If not, click on the "File" pull down window and select "New."

2. Enter the labels and data as shown here:

3. Click on the "Plot" menu, slide down to "Contingency Tables."

The following dialog box will appear:

4. Select "Status" as the "Row Labels:" and both "Current" and "Late" as the "Table entries:"

5. Now just click on the "Chi-squared test" tab

From this output, we would make the following decision and conclusion:

Decision: Reject H0

Conclusion: At an alpha level of .05, employees are significantly more likely to be current on their tuberculosis immunization than are physicians, (1, N = 44) = 5.76, p = .0164.