Barrons AP Psychology 7th edition

you do not agree. There are two main problems with Pooja’s conclusion, and describing either one would
earn you the point. One problem is that Pooja confuses causation with correlation, and you could score
this point by explaining that problem in one of two ways. It may be that taking private lessons causes
students to improve, but it also may be that students who are improving are more likely to seek out private
lessons. Alternatively, you could explain that because Pooja does not run an experiment and randomly
assign students to take private lessons or not, it could also be that some third factor (such as, practice
time) is responsible both for the improvement and for the decision to take private lessons.
The second major problem with Pooja’s conclusion is the size of the difference between the groups—
4.5 versus 4.7. This small difference is unlikely to be statistically significant—that is, such a small
difference is very likely to be due to chance.