6) (8 pts) According to the Centers for Disease Control and Prevention, 46.3% of all ninth-grade students in the United States have tried cigarette smoking. Use the Central Limit Theorem to approximate the probability that in a random sample of 1000 ninth graders, more than 48% of the sample have tried cigarette smoking: 0.463 - 0.48 / √(0.463 * (1 - 0.463) / 1000) = 2. Plugging this value into the inverse t-distribution function with 999 degrees of freedom, we get 0.0502.
QD = 0.463 - 0.48
PU-Al
7) (9 pts) In a clinical trial for Chantix (a drug used as an aid to stop smoking), 19 out of 129 people receiving Chantix experienced insomnia, while 13 out of 805 receiving the placebo experienced insomnia. Construct a 95% confidence interval for the difference between the proportion experiencing insomnia between the Chantix group and the placebo group: 2 - Z * √((p1 * (1 - p1) / n1) + (p2 * (1 - p2) / n2))
2 - Z * √((19/129 * (1 - 19/129) / 129) + (13/805 * (1 - 13/805) / 805))