Use Table V in Appendix A to determine the tpercentile that

Use Table V in Appendix A to determine the t-percentile that is required to construct each of the following two-sided confidence intervals. Round the answers to 3 decimal places.

(a) Confidence level = 95%, degrees of freedom = 18

(b) Confidence level = 95%, degrees of freedom = 28

(c) Confidence level = 99%, degrees of freedom = 18

(d) Confidence level = 99.9%, degrees of freedom = 16

Solution

a)
Critical Value
The Value of |t | with n-1 = 18 d.f, 95% Confidence is 2.101
b)

The Value of |t | with n-1 = 28 d.f, 95% Confidence is 2.048
c)

The Value of |t | with n-1 = 18 d.f, 99% Confidence is 2.878
d)

The Value of |t | with n-1 = 16 d.f, 99.9% Confidence is 4.105