Question

construct the indicated confidence interval for the population mean ų using the t-distribution. Assume the population is normally distributed.

c= 0.95
x= 12.6
s=3.0
n=9
___,____

Answer 1

We know that formula for confidence interval is

CI = x_bar t*(s/n)

n =9

Df =n-1 = 9-1=8

t value for 95% confidence interval with 8 degree is 2.306.

CI = 12.6 2.306*(3/9)

= 12.6 2.306

CI = 12.6 - 2.306 and CI = 12.6 + 2.306

= 12.294 = 14.906

So 95% confidence interval is (12.294,14.906).