Answer
We are 95% confident that the standard deviation is between 30.3 and 47.5.
Work Step by Step
The round-off rule says that we should round the boundaries of the interval by one more decimal place than the sample values. Then the interval becomes: $\sigma^2 $ is between 916.6 and 2252.1. We are 95% confident that the standard deviation is between $\sqrt{916.6}=30.3$ and $\sqrt{2252.1}=47.5.$
