Which critical value is appropriate for a 99% confidence level where nequals17, sigma is unknown, and the population appears to be normally distributed? A. z Subscript alpha divided by 2equals2.567 B. t Subscript alpha divided by 2equals2.921 C. z Subscript alpha divided by 2equals2.583 D. t Subscript alpha divided by 2equals2.898

t Subscript alpha divided by 2 = 2.921

Step-by-step explanation:

With sample sizes lower than 30, we use the t-test.

Otherwise, we use the z-test.

Here, n = 17

So we use the t-test.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 17 - 1 = 16

Now, we have to find a value of T, which is found looking at the t table, with 16 degrees of freedom(y-axis) and a confidence level of 0.99(). So we have T = 2.921

So the correct answer is:

t Subscript alpha divided by 2 = 2.921

where are the choices?