Recently, an automobile insurance company performed a study of a random sample of 15 of its customers to determine if there is a positive relationship between the number of miles driven and the age of the driver. The sample correlation coefficient is r = .38. Given this information, and assuming that the test is to be performed at the .05 level of significance, which of the following is the correct test statistic?
A) t = 1.4812
B) t = 1.7709
C) z = 2.114
D) t = 1.74

Question

Quizplus · Accepted Answer

The correct test statistic for testing the significance of a correlation coefficient, r, with a sample size of n is given by the formula $t = \frac{r\sqrt{n-2}}{\sqrt{1-r^2}}$. Using the given sample correlation coefficient, r = .38, and the sample size, n = 15, the calculation yields a t-value close to 1.4812, making option A the correct choice.

Recently, an Automobile Insurance Company Performed a Study of a Random