A physician studying sleep disorders wants to determine the effect of caffeine consumption on sleep. She collects a random sample of 17 pairs of data, where each pair consists of a person's daily caffeine consumption (x) and number of hours of sleep the following night (y). She calculates the test statistic for this data to be r = -0.325, the mean caffeine consumption (a) to be 3.95 g, the mean amount of sleep (y) to be 6.68 hours, and the regression equation to be y = - 0.39x + 7.93. Use a significance level of a = 0.10, and find the best predicted amount of sleep (in hours) for a person who consumed 2.1 g of caffeine the day before. O 6.68 O7.11 O 6.39 O 3.95 None of these Submit