In: Math
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. Nicotine in menthol cigarettes 80% confidence; n=27, s=0.29 mg.
Solution :
Given that,
s = 0.29
s2 = 0.0841
2L = 2/2,df = 35.563
2R = 21 - /2,df = 17.292
The 80% confidence interval for is,
(n - 1)s2 / 2/2 < < (n - 1)s2 / 21 - /2
26 * 0.0841 / 35.563 < < 26 * 0.0841 / 17.292
0.25 < < 0.36
(0.25 , 0.36)