# Setting the options for Significance (t-test)

You can control the way t-tests and U-tests are calculated by changing the figures in the **Summary Statistics** tab of the **Analysis Definition **dialog.

If you want these figures to be the default values for the survey, you must set them in the **Analysis tailoring** dialog. This also has a **Summary Statistics** tab. You open the Analysis Tailoring dialog by selecting **Analysis **from the **Tailor **menu.

- Open the appropriate dialog (Analysis Definition or Analysis tailoring)
- Click the Summary Statistics tab
- Select the Significance (t-test) in either of the columns. The possible options appear below.

**Comparison**enables you to select the base used when comparing the mean of base to the mean of each category on your table. Either use:**Base**: the mean for all respondents**Base less current:**the mean for respondents that are not included in the category being compared.

**Score**is the score applied for all calculations**Decimal places**give the number of decimal places the significance (t-test) value is calculated to. (It is usual to keep the significance (t-test) decimal places to 0 and the mean decimal places to 2.)