Question

Determine the t-value in each of the cases.

A.) Find the t-value such that the area in the right tail is 0,005 with 16 degrees of freedom. (Round to three decimal places as needed).

B.) Find the t-value such that the area in the right tail is 0.05 with 11 degrees of freedom. (Round to three decimal places as needed.)

C.) Find the t-value such that the area left of the t-value is 0.20 with 19 degrees of freedom. (Hint: Use symmetry).

(Round to three decimal places as needed).

D.) Find the critical t-value that corresponds to 95% confidence. Assume 21 degrees of freedom.

(Round to three decimal places as needed).

Answer 1

A) We want to find the t-value such that the area in the right tail is 0.005 with 16 degrees of freedom.

Excel command : TINV(2 * 0.005, 16) = 2.921

=> Critical value is 2.921

B.) We want to find the t-value such that the area in the right tail is 0.05 with 11 degrees of freedom.

Excel command : TINV(2 * 0.05, 11) = 1.796

=> Critical value is 1.796

C.) We want to find the t-value such that the area left of the t-value is 0.20 with 19 degrees of freedom.

Excel command : TINV(2 * 0.20, 19) = 0.861

since, we are given area to the left of the t-value is given, the required critical value is negative.

=> Critical value is -0.861

D.) We want to find the critical t-value that corresponds to 95% confidence. Assume 21 degrees of freedom.

Excel command : TINV(0.05, 21) = 2.080

=> Critical value are -2.080, 2.080