Univariate Analysis (ViSta-UniVar) provides techniques for comparing means of two populations. ViSta-UniVar can compare two sets of data whether they are independent or paired (dependent). It tests whether the means of the two groups are significantly different, and reports the confidence interval for the difference in means. 

For samples from independent populations ViSta-UniVar computes Student's T-test and the Mann-Whitney test. For paired (dependent) samples the paired-samples T-Test and the Wilcoxon Signed Rank Test are computed. Student's T-test is used when there is a single sample. ViSta-UniVar can also use the T-test to compare the mean of one population to a pre-specified hypothetical mean. If the population variance is known, then the Z-test is substituted for the T-test.

The T-test (and Z-test) test the null hypothesis that the means of the populations from which the data are sampled are equal. The Mann-Whitney U-test and the Wilcoxon Signed Rank Test use the null hypothesis that both populations are identically distributed.

The ViSta-UniVar visualization presents plots to help you assess the normality assumption.
