Lets first ask if students who are coached increased their scores significantly, on average. a. You could

Question:

Let’s first ask if students who are coached increased their scores significantly, on average.

a. You could use the information on the Coached line to carry out either a two-sample t test comparing Try 1 with Try 2 or a paired t test using Gain. Which is the correct test? Why?

b. Carry out the proper test. What do you conclude?

Coaching companies claim that their courses can raise the SAT scores of high school students. Of course, students who retake the SAT without paying for coaching generally raise their scores. A random sample of students who took the SAT twice found 427 who were coached and 2733 who were uncoached. Starting with their Verbal scores on the first and second tries, we have these summary statistics:

Try 1 Try 2 Gain 1. SX 305 =0.200 1526 SX SX 305 305 0.200 1526 305 = 0.200 1526 305 305 0.200- 1526 0.200 0.200 : 1526 1526 Coached 427 500 92 529 97 29 59 Uncoache 2733 506 101 527 101 21 52