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Statistical test functions

This section describes functions for statistical tests, which are divided into three categories. The functions can be used in both the load script and chart expressions, but the syntax differs.

## Chi-2 test functions

Generally used in the study of qualitative variables. One can compare observed frequencies in a one-way frequency table with expected frequencies, or study the connection between two variables in a contingency table.

## T-test functions

T-test functions are used for statistical examination of two population means. A two-sample t-test examines whether two samples are different and is commonly used when two normal distributions have unknown variances and when an experiment uses a small sample size.

## Z-test functions

A statistical examination of two population means. A two sample z-test examines whether two samples are different and is commonly used when two normal distributions have known variances and when an experiment uses a large sample size.