1. A biologist hypothesizes that the mean life expectancy of a mosquito is 14 days. Researchers believe the true mean is less than 14 days and they plan a hypothesis test at the 5% significance level on a random sample of 60 of these mosquitos. If the alternative hypothesis is correct, for which of the following values of ? is the power of the test greatest?

a.? = 9

b.? = 7

c.? = 10

d.? = 14

e.? = 18

2. Eighteen pairs of measurements were taken at random to estimate the relation between variables X and Y. A least-squares line was fitted to the collected data. The resulting residual plot is shown.

O 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Time, seconds12 11 10 8 - 6 Number of Dogs 6 4 2 2 1 0 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 Time, seconds