A team in the Department of Institutional Review at a large university wanted to study the relationship between completing an internship during college and students' future earning potential. From the same graduating class, they selected a random sample of 80 students who completed an internship and 100 students who did not complete an internship and examined their salaries 5 years past graduation. They found that there was a statistically higher mean salary for the internship group than for the non-internship group. Which of the following interpretations do you think is the most appropriate?
A. More students should take internships because having an internship produces a higher salary.
B. There could be a confounding variable, such as student major, that explains the difference in mean salary between the internship and no intership groups.
C. You cannot draw any valid conclusions because the samples are not the same size.