A dietician decides to study the no nighttime snack diet systematically to determine if such a diet has a significant effect on weight. She obtains a random sample of late-night snackers, weighs them, instructs them to elimate food from their diet after 9pm for 30 days, weighs them again, and analyzes the results to determine if there are any weight differences using an = 0.05.

D = 8.63

S_D = 9.2