A researcher finds that students who listen to classical music in elementary
school tend to have better grades in high school. There was no random assignment
to conditions or manipulation of an independent variable. In other words, they
didn't just look at a bunch of random students. We might not even know which
students they looked at. But then the researcher recommends that children should
listen to classical music, because that will cause them to perform better in
school. What's wrong with this logic? Select all that apply.