What does the T-test measure?

What does the T-test measure?

• A. if two means are statistically different from each other
• B. the rate of mutation in a population
• C. the average difference between medians
• D. the slope of a regression line

Answer: (A)

The t-test is a tool for assessing whether the average values of two groups are different in a statistically meaningful way. It works by comparing the observed difference between the group means to how much that difference would be expected to vary due to random sampling if the true population means were actually equal. The result is a t-statistic and a p-value; a small p-value indicates that such a difference is unlikely under the assumption of equal means, leading to the conclusion that the two means are different. This makes sense for the given question: the t-test specifically measures whether two means differ beyond what random chance would predict. It isn’t about mutation rates, which are a population-genetics concept; it isn’t a test of medians (that uses nonparametric methods like Mann-Whitney or median tests); and it isn’t about the slope of a regression line (that’s analyzed with regression methods).

The t-test is a tool for assessing whether the average values of two groups are different in a statistically meaningful way. It works by comparing the observed difference between the group means to how much that difference would be expected to vary due to random sampling if the true population means were actually equal. The result is a t-statistic and a p-value; a small p-value indicates that such a difference is unlikely under the assumption of equal means, leading to the conclusion that the two means are different.

This makes sense for the given question: the t-test specifically measures whether two means differ beyond what random chance would predict. It isn’t about mutation rates, which are a population-genetics concept; it isn’t a test of medians (that uses nonparametric methods like Mann-Whitney or median tests); and it isn’t about the slope of a regression line (that’s analyzed with regression methods).