Question

Consider a right-tailed test (upper tail) and a sample size of 40 at the 95% confidence level. The value of t is ________.

a. +2.023
b. -2.023
c. -1.685
d. +1.685

Answer 1

The correct option is d.

Explanation:

The directional hypothesis is:

`H_(a):\mu>\mu_(0)`

The sample size is, n = 40.

The significance level is:

`\alpha =1-0.95=0.05`

Use the t-table to compute the right-tailed t-critical value as follows:

`t_(\alpha,\ (n-1))=t_(0.05, (40-1))`

`=t_(0.05, 39)\\\\\approx t_(0.05, 40)\\\\=1.684\\\\\approx 1.685`

The value is positive since the directional hypothesis suggests that the test is right tailed.

The correct option is d.