TABLE 8-10
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 Table 8-10, the president can be 90% 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

Looking at Table 8-10, with a sample size of 250 and 7 students reporting illicit drug use, the 90% confidence interval for the proportion of students who use drugs is 0.012 to 0.052. As this interval does not include a value higher than the targeted level of 0.05 (or 5%), we can be 90% confident that no more than 5% of the students at the university had used illicit drugs during the last 12 months. Therefore, the statement is true.

TABLE 8-10 The President of a University Is Concerned That Illicit Drug