Question

for a hypothesis comparing two population means, what is the critical value for a one-tailed hypothesis test, using a 5percent level of significance level, with both sample sizes equal to 13? the standard deviations for the samples are 5 and 7. assume the population standard deviations are unequal

Answer 1

If you have equal sample sizes and unequal standard deviations, a Welch's t-test might be appropriate. Check degrees of freedom for this type of test before checking the appropriate table to determine critical value.