What data is used in the Two group comparison (t-test)

Question

ID 30

Category Qlucore Omics Explorer Analysis

Date Created 2009-05-12 19:03:52

Date Updated 2017-01-13 13:41:49

When the two group comparison test is performed (student's t-test), is the test done by using the imputed data, or the original data?

Answer

Qlucore Omics Explorer uses the "classical" t-test as default. This is reached from the standard tab in the statistics dialog. Other tests can be reached from the Extended tab.

If there are missing values, the imputed values are used.

The user shall be aware of that if data is imputed with the simple average method, then the sample variance tend to underestimate the real variance.

The t-test assumes that data is normally distributed. It can work well also for data that is not normally distributed. If data is reasonable normal distributed the t-test is robust for the following differences in sample sizes and variance.

1. The t-test is optimal even if the sample groups are of different size as long as the variances are the same. 2. The t-test is robust if the variance differs between the groups but the groups are of roughly equal size.