Question

A researcher collects a sample of 16 measurements from a population and wishes to find a​ 90% confidence interval for the population mean. What value should he use for​ t*? (Recall that the number of degrees of freedom for a​ one-sample t-test is given by equals df=​1, where n is the sample​ size.) LOADING... Click the icon to view the​ t-distribution table.

To find a​ 90% confidence interval for the population​ mean, he should use nothing for​ t*. ​(Round to three decimal places as​ needed.)

Answer 1

solution

(A)n = 16

Degrees of freedom = df = n - 1 =16 - 1 = 15

At 90% confidence level the t is ,

= 1 - 90% = 1 - 0.90 = 0.1

/ 2 = 0.1 / 2 = 0.05

t /2,df = t0.05,15 =1.753    ( using student t table)

(B)df=1

At 90% confidence level the t is ,

= 1 - 90% = 1 - 0.90 = 0.1

/ 2 = 0.1 / 2 = 0.05

t /2,df = t0.05,1 =6.314 ( using student t table)