15.34 Is math the key to success in college? A newspaper account of a College Board study of 15,941 high school graduates noted that minority students who take algebra and geometry in high school succeed in college at a rate that is nearly the same as whites. Here is part of the opening of a newspaper account of the study:

The link between high school math and college graduation is “almost magical,” says College Board President Donald Stewart, suggesting “math is the gatekeeper for success in college.”

“These findings,” he says, “justify serious consideration of a national policy to ensure that all students take algebra and geometry.”

What lurking variables might explain the association between taking several math courses in high school and success in college? Explain why requiring algebra and geometry may have little effect on who succeeds in college.