What test is used to compare more than two groups?

The correct answer is C, ANOVA (analysis of variance), which is specifically designed to compare the means of three or more groups to determine if there are statistically significant differences among them. ANOVA tests the null hypothesis that all group means are equal. If the results indicate significant differences, further analysis can be done to identify which specific groups differ from each other.

This method is advantageous when dealing with multiple groups, as it controls the overall type I error rate that would increase if multiple t-tests were conducted instead. While the independent and dependent t-tests are effective for comparing two groups, they are not suitable for situations where more than two groups need to be analyzed. A two-tailed t-test is also limited to the comparison of two means and does not extend to multiple groups, which is why ANOVA is the robust choice in this context.