Does coaching raise SAT scores? Because many students score higher on a second try, even without coaching, a study looked at a simple random sample of 4200 students who took the SAT twice. Of these, 500 had taken coaching courses between their two attempts at the SAT. The study compared the average increase in scores (out of the total possible score of 2400) for students who were coached with the average increase for students who were not coached.
The study is 95 percent confident that the difference between average scores for coached and uncoached students is between 28 and 57 points. To be 99 percent confident, the range of points would be:

Question

Quizplus · Accepted Answer

When the level of confidence is higher, the margin of error needs to be smaller. This means that the confidence interval will be narrower, but the trade-off is that there is a higher chance of making a type 1 error (rejecting a true null hypothesis). Therefore, to be 99 percent confident, the range of points would need to be wider than the 95 percent confidence interval.

Does Coaching Raise SAT Scores? Because Many Students Score Higher