Coaching for the SAT. Use this information for Exercises 37–39. The College Board reports that a pretest and post-test study was done to investigate whether coaching had a significant effect on SAT scores. The improvement from pretest to post-test was 29 points for the coached sample of students, with a standard deviation of 59 points. For the uncoached students, the pretest to post-test improvement was 21 points with a standard deviation of 52 points.

Question 10.89

38. Refer to Exercise 37.

  1. Find a point estimate of the difference in population means.
  2. Find a 99% confidence interval for the difference in population means.
  3. Determine whether the population means differ, at level of significance .