How do I solve this equation?

Question

A study of life expectancy showed that a random sample of 6

 states had a standard deviation of 0.6

 deaths per year. Find the 90%

 confidence intervals of the variance and standard deviation. Assume the variable is normally distributed. Use the chi-square distribution table to find any chi-square values to three decimal places. Round your final answers to one decimal place.

Answer 1

X^2 is chi-square distribution

(n-1)s^2 (n-1)s^2

------------ < variance < -----------

X^2 0.05 X^2 0.95

where n = 6

s^2 = 0.6*0.6 = 0.36

X^2 0.05, 5 DOF = 11.07

X^2 0.95, 5 DOF = 1.15

Plug value into equations above to get confidence interval limits for variance

Take square root of confidence interval limits to get confidence interval limits for standard deviation