In: Statistics and Probability
the standard deviation of the diameter of 28 oranges was 0.34 inch. find the 99% confidence interval of the true standard deviation of the diameter of the orages.
Solution :
Given that,
s = 0.34
s2 = 0.1156
2L = 2/2,df = 49.645
2R = 21 - /2,df = 11.808
The 99% confidence interval for is,
(n - 1)s2 / 2/2 < < (n - 1)s2 / 21 - /2
27 * 0.1156 / 49.645 < < 27 * 0.1156 / 11.808
0.25 < < 0.51
(0.25 , 0.51)