Question

A chocolate chip cookie manufacturing company recorded the number of chocolate chips in a sample of 70 cookies. The mean is 22.66 and the standard deviation is 2.99. Construct a 98​% confidence interval estimate of the standard deviation of the numbers of chocolate chips in all such cookies.

__ chocolate chips < standard deviation < __ chocolate chips

round to two decimal places

Answer 1

From chi-square table,

chi square critical value at 0.02 significance level with 69 df = 44.639 , 99.227

98% confidence interval for is

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

sqrt [ 69 * 2.992 / 99.227 ] < < sqrt [ 69 * 2.992 / 44.639 ]

2.49 < < 3.72

answered by: anonymous