Another sample of candies was opened and recorded. The sample size was 30. Below is the summary of the sample. Assume the standard deviation is known. red 3.16 1.61 color mean sd 1 green 2.63 1.42 total 9.1 2.54 90% CI for mean number of red candies z(a/2) = z(0.10/2) = Lower Upper 2 blue 3.32 1.42 1.6448536 mean - z(a/2)*(sd/sqrt(n)) 2.6764614 mean + z(a/2)*(sd/sqrt(n)) 3.6435386 A 90% confidence interval for the standard deviation of the total number of candies. Chi(a/2,n-1) = chi(0.10/2,29) chi(1-a/2,n-1) = chi(1-0.1/2,29) = 42.556968 17.708366 lower s*sqrt((n-1)/chisq(a/2,n-1)) 2.0967535 upper s*sqrt((n-1)/chisq(1-a/2,n-1)) 3.2504498