The sample average in one sub-sample is xa = 4.3 and the sample standard deviation is σa = 5.4. the sample average in the second sub- sample is xb = 2.1 and the sample standard deviation is σb = 6.7. the size of the first sub-sample is na = 83 and the size of the second sub-sample is nb = 92. we are interested in testing the null hypothesis that the ratio of variances var(xa)/var(xb) is equal to one against the two-sided alternative. the null is:

select one:

a. not rejected with a significance level of 5%.

b. rejected with a significance level of 5%, but not with a significance level of 1%.

c. rejected with a significance level of 1%, but not with a significance level of 0.1%.

d. rejected with a significance level of 0.1%