Chapter 8.3, Problem 62E

a)

To determine

To find the critical value t*

Answer to Problem 62E

The critical value t* = 1.796

Explanation of Solution

Given:

Sample size = n = 12

Confidence level = 0.90

First need to find degrees of freedom:

  $df=n-1=12-1=11$

Level of significance = a = 0.10

Therefore,

t_11,a/2=1.796 ….Using excel formula, =TINV(0.1,11)

b)

To determine

To find the critical value t*

Answer to Problem 62E

The critical value t* = 2.045

Explanation of Solution

Given:

Sample size = n = 30

Confidence level = 0.95

First need to find degrees of freedom:

  $df=n-1=30-1=29$

Level of significance = a = 0.05

Therefore,

t_11,a/2=1.045….Using excel formula, =TINV(0.05,29)

c)

To determine

To find the critical value t*

Answer to Problem 62E

The critical value t* = 2.678

Explanation of Solution

Given:

Sample size = n = 58

Confidence level = 0.999

First need to find degrees of freedom:

  $df=n-1=58-1=57$

Level of significance = a = 0.01

Therefore,

t_11,a/2=2.678….Using excel formula, =TINV(0.01,57)