TABLE 8-12
The president of a university is concerned that illicit drug use on campus is higher than the 5% acceptable level. A random sample of 250 students from a population of 2000 revealed that 7 of them had used illicit drug during the last 12 months.
-Referring to Table 8-12, using the 90% one-sided confidence interval, the president can be 95% confident that no more than 5% of the students at the university had used illicit drug during the last 12 months.

Question

Quizplus · Accepted Answer

The sample proportion of students using illicit drugs is 7/250 = 0.028 or 2.8%. A 90% one-sided confidence interval would not provide 95% confidence, and the interval would likely include values above 5%, indicating that the president cannot be 95% confident that the usage is below 5%.

TABLE 8-12 The President of a University Is Concerned That Illicit Drug