Use this dialog to select the output generated by a randomization test of the difference between two groups, and the options used in the test.

## Display

Specifies which items are displayed in the Output window or the Graphics window.

Summary and estimates |
A summary, estimates and the randomization test probability. Additional information is displayed when the t-test method is used which includes the lower and upper confidence limits. |

Histogram of samples |
A histogram of the randomization distribution of the statistic with the observed statistic marked on the graph. |

## Type of test

Lets you choose either a one- or two-sided t-test. A two-sided test looks for differences either side of 0, whereas a one-sided test checks whether the mean is greater than or less than the given mean.

## Estimate of variance for t-test

This option is only available when the two-sample t-test method is selected. For a two-sample t-test you can choose which method is used for estimate of variances for the test statistic.

Automatic |
Uses a pooled estimate unless there is evidence of unequal variances. |

Pooled |
Always uses a pooled estimate of the standard deviation for the test, i.e. a common standard deviation that is formed from the average variance over the two groups. |

Separate |
Estimate the standard deviation for the test using separate variances. |

## Confidence limits (%)

This option is only available when the two-sample t-test method is selected. This lets you control the limits for the calculation of the confidence interval for the t-test. The limit is expressed as a percentage in the range 0-100.

## Seed for randomization

This gives a seed to initialize the random number generation used for resampling the data. Using zero initializes this from the computer’s clock: specifying a non-zero value gives a repeatable analysis.

## See also

- Randomization test for two groups menu
- Randomization test store options saving the randomized statistics
- TTEST procedure in command mode