There is also another part to this question that I have been working on, but have been unsuccessful. So I have to find the confidence interval around variance with minimum length. I figured that I have to differentiate the length of the CI, namely the upper limit - the lower limit, and set that quantity to 0, but I am having a lot of trouble differentiating the 1/(chi-square) part....

Someone please help me on this.... Thank you so much!