In: Statistics and Probability
a.Use the Student's t distribution to find tc for a 0.95 confidence level when the sample is 9. (Round your answer to three decimal)
b.Use the Student's t distribution to find tc for a 0.99 confidence level when the sample is 31. (Round your answer to three decimal places.)
a
Degrees of freedom = df = n - 1 =9 - 1 = 8
At 95% confidence level the t is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2= 0.05 / 2 = 0.025
t /2,df = t0.025,8 = 2.306 ( using student t table)
b.
Degrees of freedom = df = n - 1 =31 - 1 = 30
At 99% confidence level the t is ,
= 1 - 99% = 1 - 0.99 = 0.01
/ 2 = 0.01 / 2 = 0.005
t /2 df = t0.005,30 =2.750 ( using student t table)