Question

A simple random sample from a population with a normal distribution of 104 body temperatures has x=98.50degrees F and s=0.69degrees F. Construct a 90​% confidence interval estimate of the standard deviation of body temperature of all healthy humans

____F<o<____ F

Answer 1

df = n -1 = 104 - 1 = 103

chi square critical values at 0.10 significance level with 103 df = 80.582 , 127.689

90% confidence interval for is

Sqrt [ ( n -1) S2 / U ] < < Sqrt [ ( n -1) S2 / L ]

sqrt [ 103 * 0.692 / 127.689 ] < < sqrt [ 103 * 0.692 / 80.582 ]

0.6197 < < 0.7801