Question 8 A sleep disorder specialist wants to test the effectiveness of a new drug that is reported to increase the number of hours of sleep patients get
during the night. To do so, the specialist randomly selects nine patients and records the number of hours of sleep each gets with and without the
new drug. The results of the two-night study are listed below. Using this data, find the 95% confidence interval for the true difference in hours
of sleep between the patients using and not using the new drug.
Let d = (hours of sleep with the new drug)-(hours of sleep without the new drug). Assume that the hours of sleep are normally distributed for
the population of patients both before and after taking the new drug.
Patient
5
8 9
Hours of sleep without the drug 2.3 2.9 5.4 1.8 1.8 7.2 1.9 5.9 5
Hours of sleep with the new drug 3 4.9 7.4 3.7 3.9 7.9 4.2 8.2 6.7
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