The managing director of a pharmaceutical copany that has recently developed a new non-prescription sleeping pill wants to measure its effectiveness. Her assistant recruits five individuals selected ant random to participate in a preliminary experiment. The experiment is performed over 2 nights. On 1 night the subject takes the sleeping pill, and on the other he or she takes a placepo. Estimate with 95% confidence between the average assembly times of the two pills. The order in which the pills are taken by each individual is random.

Number of hours of sleep

SubjectSleeping pill (X1)Placebo (X2)Difference (X_D)

17.36.80.5

28.57.90.6

36.46.00.4

49.08.40.6

56.96.50.4