Question

(a) Use the Student's t distribution to find t_c for a 0.99 confidence level when the sample is 17. (Round your answer to three decimal places.)

(b) Use the Student's t distribution to find t_c for a 0.95 confidence level when the sample is 15. (Round your answer to three decimal places.)

Answer 1

solution:

Degrees of freedom = df = n - 1 = 17- 1 = 16

At 99% confidence level the t is ,

= 1 - 99% = 1 - 0.99 = 0.01

/ 2 = 0.01 / 2 = 0.005

t /2  df = t0.005,16= 2.921 ( using student t table)

b

n = Degrees of freedom = df = n - 1 =15 - 1 = 14

At 95% confidence level the t is ,

= 1 - 95% = 1 - 0.95 = 0.05

  / 2= 0.05 / 2 = 0.025

t /2,df = t0.025,14 = 2.145 ( using student t table)