SCENARIO 8-13
The president of a university is concerned that illicit drug use on campus is higher than the 5% targeted level.A random sample of 250 students from a population of 2,000 revealed that 7 of them had used illicit drugs during the last 12 months.
-Referring to Scenario 8-13,using the 90% one-sided confidence interval,the president can be 85% confident that no more than 5% of the students at the university had used illicit drugs during the last 12 months.

Question

Quizplus · Accepted Answer

A one-sided confidence interval is used when the hypothesis is directional, which is the case here as the president is concerned that drug use is higher than the targeted level of 5%. A one-sided 90% confidence interval will provide a lower bound for the true proportion of students using illicit drugs. If the lower bound is less than 5%, then the president can be 85% confident that no more than 5% of students have used drugs in the last 12 months. Based on the sample of 250 students and 7 reporting drug use, the lower bound for the confidence interval is 0.0176, which is less than 5%. Therefore, the statement is true.

SCENARIO 8-13 The President of a University Is Concerned That Illicit Drug