20 pts to whoever helps!!

The standard deviation of a simple random sample of 40 calling times on a pay phone is found to be 2.6 minutes. Find the statistic to test a claim that the standard deviation of all phone calls on a pay phone is less than 2.9 minutes. Use a 0.05 significance level.
a. 32.152
b. 31.348
c. 48.519
d. 34.966

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Work Shown:

We will never use the alpha = 0.05 value when computing the test statistic. So we can ignore alpha for this particular problem.

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n = 40 is the sample size.

s = 2.6 is the sample standard deviation

= sigma = 2.9 is the population standard deviation (ie the claimed standard deviation for all the pay phones)

Test Statistic for chi-square