A two-sided test is performed by default:

Perform a two-sided test or a one-sided alternative:

Perform tests with one-sided alternatives when

is given:

Set the significance level for diagnostic tests:

By default,

is used:

The significance level is also used for

and

:

By default normality and equal variance are tested:

If assumptions are not checked, some test results may differ:

Diagnostics can be controlled as a group using

All or

None:

Verify all assumptions:

Check no assumptions:

Diagnostics can be controlled independently:

Assume normality but check for equal variances:

Only check for normality:

Unlisted assumptions are not tested:

Here, normality is assumed:

The result is the same but a warning is issued:

Bypassing diagnostic tests can save compute time:

It is often useful to bypass diagnostic tests for simulation purposes:

The assumptions of the test hold by design, so a great deal of time can be saved:

The results are identical: