Question

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 = 15 (b) Confidence level = 95%, degrees of freedom = 22 (c) Confidence level = 99%, degrees of freedom = 16 (d) Confidence level = 99.9%, degrees of freedom = 14 @ @ OS

Answer 1

Solution :

(a)
=> confidence level = 95% => α = 1 - 0.95 = 0.05

=> degrees of freedom df = 15

=> t0.05,15 = 2.131

(b)
=> confidence level = 95% => α = 1 - 0.95 = 0.05

=> degrees of freedom df = 22

=> t0.05,22 = 2.074

(c)
=> confidence level = 99% => α = 1 - 0.99 = 0.01

=> degrees of freedom df = 16

=> t0.01,16 = 2.921

(d)
=> confidence level = 99.9% => α = 1 - 0.999 = 0.001

=> degrees of freedom df = 14

=> t0.001,14 = 4.140