Determine the t-value in each of the cases.

(a) Find the t-value such that the area in the right tail is 0. 10 with 22 degrees of freedom.

(Round to three decimal places as needed.)

(b) Find the t-value such that the area in the right tail is 0.01 with 15 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 16 degrees of freedom. [Hint: Use symmetry.]

(Round to three decimal places as needed.)

(d) Find the critical t-value that corresponds to 90% confidence. Assume 28 degrees of freedom.

(Round to three decimal places as needed.)