Refer to Exercise 15.6. Suppose that two more groups of 10 men each are tested on the number of nonsense syllables they can remember after 5 minutes. However, this time the 65-70-year-olds are given a mild dose of ampakine CX-516. Do the data provide sufficient evidence to conclude that this drug improves memory in men aged 65-70 compared with that of 20-year-olds? Use an appropriate level of a.

Exercise 15.6.
In some tests of healthy, elderly men, a new drug has restored their memory almost to that of young people. It will soon be tested on patients with Alzheimer's disease, the fatal brain disorder that destroys the mind. According to Dr. Gary Lynch of the University of California, Irvine, the drug, called ampakine CX-516, accelerates signals between brain cells and appears to significantly sharpen memory. 2 In a preliminary test on students in their early 20s and on men aged 65-70, the results were particularly striking. After being given mild doses of this drug, the 65-70-year-old men scored nearly as high as the young people. The accompanying data are the numbers of nonsense syllables recalled after 5 minutes for 10 men in their 20s and 10 men aged 65-70. Use the Wilcoxon rank sum test to determine whether the distributions for the number of nonsense syllables recalled are the same for these two groups.

20s 11 7 6 8 6 9 10 3 6 65-70s 1 9 6 8 7 8 57 10 3 20s 3 6 4 8 71 12 78 65-70s 1 0 4 25 2 2 3