Which statistical test is used to compare mean values of a continuous variable between two groups?

The t-test is used to compare the mean values of a continuous variable between two groups. This statistical test assesses whether the means of two independent samples are significantly different from one another, making it ideal for scenarios where researchers want to determine if a specific intervention or exposure leads to different outcomes in two distinct populations or conditions.

The t-test works under certain assumptions, such as the data being approximately normally distributed and the variances of the two groups being equal, although there are variations of the t-test that can be used if these assumptions do not hold.

In contrast, the chi-square test is used for categorical data to examine the association between two or more groups. ANOVA (Analysis of Variance) is employed when comparing means across three or more groups. A case-control study is an observational research design typically used to identify factors associated with outcomes rather than comparing mean values. Thus, the choice of the t-test is particularly suited for the purpose of comparing mean values between two groups.