Assumptions underlying the independent-measures t-test According to the theory of stereotype threat, situational pressures can lead to decreased performance on tests of cognitive abilities. Joshua Aronson tested how Caucasian engineering students performed on a math test when placed under a form of situational pressure by randomly assigning 100 of these students to either the control or experimental groups. The control group was told that they were taking a test of general math ability. Members of the experimental group were presented with several news articles discussing the increasing difference in math scores between Asian and Caucasian students and were told that the purpose of the test was to explore these differences.
Would it be valid for Dr. Aronson to use the independent-measures t-test to test whether drawing attention to stereotypes about racial groups and math ability affects math scores?

A. No, because the two populations from which the samples are selected are not normally distributed.
B. Yes, because the sample size is large and there is no reason to believe the assumptions of the independent-measures t-test are violated.
C. No, because the two groups studied are not independent.
D. No, because the variances within the two samples are different.

No, it won't be valid for Dr. Aronson to use the independent-measures t-test to test whether drawing attention to stereotypes about racial groups and math ability affects math scores because the variances within the two samples are different . Also, while using an independent t-test, the basis is that two-sample should have the same variance. The given problem did not satisfy this norm.