The infamous psychologist, Dr. Visegrips, claims that his secret sleep tapes cause people to become better at basic algebra "All you have to do," the doctor explains, "is listen to my tapes while you sleep at night, and you'll be better at algebra in two months". A math teacher at a local high school has expressed interest but demands evidence. Five students from this school are randomly selected. They take an algebra skills test, listen to Dr. Visegrips' tape for two months while they sleep, and then take a second test. The test scores are given here. Test scores Student A B D m Pretest 68 69 74 171 165 Posttest 70 68 75 172 68 Which of the following is the correct 99% confidence interval for the true mean difference (posttest - pretest) in scores? Select one: O a. 1.2+2.576 1.48 O b. 1.21 4.604 1.48 O c 1.2+4.604 1 48 O d. 1.2+ 2 576 148 O e. (70.6- 69.4) + 3.250 297 3 362 5 5