A STAT 200 instructor is interested in whether there is any

A STAT 200 instructor is interested in whether there is any variation in the final exam grades between her two classes Data collected from the two classes are as follows: Section 1: n1 = 28, x1 = 80, s1 = 16 Section 2: n2 = 25, x2 = 75, s2 = 12 Her null hypothesis and alternative hypothesis are: H0: = sigma1^2 = sigma2^2, and Ha: sigma1^2 > sigma2^2 Determine the test statistic. Show all work; writing the correct test statistic, without supporting work, will receive no credit. Determine the P-value for this test. Show all work; writing the correct P-value, without supporting work, will receive no credit. Is there sufficient evidence to justify the rejection of H0 at the significance level of 0.05? Explain.

Solution

The F-test: this assumes the two samples come from populations that are normally distributed. In the Options field in the 2 Variance test you will check a box to use normal distribution.

F = s1^2/s2^2

=1.778

df - 27, 24

p value = 0.07910636

As p >0.05, accept null hypothesis

The two variances can be taken as equal.