What does the student's t-test primarily compare?

The student's t-test is primarily designed to compare the means of two different groups. This statistical test assesses whether the means of the two groups are significantly different from each other, which can help determine if any observed differences are likely to be due to chance or if they reflect a true effect.

In practice, the t-test requires that the data from the two groups be normally distributed and have similar variances, which allows for a valid comparison of their means. It's particularly useful in scenarios such as clinical trials or experimental studies where researchers want to determine the effect of an intervention.

While the t-test is effective for comparing two groups, other statistical methods are better suited for comparing means across three or more groups, as well as for analyzing categorical outcomes and variances within a single group. These alternative methods include ANOVA for multiple groups and chi-square tests for categorical data.