Question

Please help :> I will give you a shiny medal :D

The july utility bills (in dollars) of 20 randomly selected homeowners in one city are listed below. Construct a 99% confidence interval for the variance, sigma^2. Assume the population is normally distributed.

Answer 1

Data:
70, 72, 71, 70, 69, 68, 70, 71, 67, 71, 70, 74, 69, 71,71,71, 72

Answer 2

So is this a hypothesis for a population standard deviation?

Answer 3

it looks like they want the confidence interval, not the hypothesis

Answer 4

I did