In: Statistics and Probability
Use the given information to find the number of degrees of freedom, the critical values chi Subscript Upper L Superscript 2 and chi Subscript Upper R Superscript 2, and the confidence interval estimate of sigma. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. Platelet Counts of Women 90% confidence; n=22, s=65.8.
Solution :
Given that,
s = 65.8
n = 22
df = 21
2R = 2/2,df = 32.671
2L = 21 - /2,df = 11.591
The 90% confidence interval for is,
(n - 1)s2 / 2/2 < < (n - 1)s2 / 21 - /2
21 * 65.8 2 / 32.671 < < 21 * 65.8 2 / 11.591
52.7542 < < 88.5665
(52.7542 , 88.5665 )