Assuming that the population variances are equal for Male and Female GPA’s, test the following sample data to see if Male and Female PhD candidate GPA’s (Means) are equal. Conduct a two-tail hypothesis test at á =.01 to determine whether the sample means are different. Do NOT do a confidence interval.

Question

Assuming that the population variances are equal for Male and Female GPA’s, test the following sample data to see if Male and Female PhD candidate GPA’s (Means) are equal.   Conduct a two-tail hypothesis test at á =.01 to determine whether the sample means are different.  Do NOT do a confidence interval.

Male GPA’s	Female GPA’s
Sample Size	12	13
Sample Mean	2.8	4.95
Sample Standard Dev	.25	.8

PsyDAG · Answer

Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√(n-1)

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.