Find the Critical Value or Values Of $\chi ^ { 2 }$

Essay

Find the critical value or values of $\chi ^ { 2 }$ based on the given information.
-With individual lines at the checkouts, a store manager finds that the standard deviation for the waiting times
on Monday mornings is 5.7 minutes. After switching to a single waiting line, he finds that for a random sample
of 29 customers, the waiting times have a standard deviation of 4.9 minutes. Use a 0.025 significance level to test
the claim that with a single line, waiting times vary less than with individual lines.