At a certain university, the average cost of books was $370 per student last semester and the population standard deviation was $80. This semester a sample of 45 students
Revealed an average cost of books of $390 per student. The Dean of Students believes
That the costs are greater this semester. What is the test value for this hypothesis?
A) 0.44
B) 0.25
C) 11.25
D) 1.68

Question

Quizplus · Accepted Answer

The test value for this hypothesis can be calculated using the formula for a one-sample z-test: $z = \frac{\bar{x} - \mu}{(\sigma / \sqrt{n})}$, where $\bar{x}$ is the sample mean, $\mu$ is the population mean, $\sigma$ is the population standard deviation, and $n$ is the sample size. Plugging in the given values: $z = \frac{390 - 370}{(80 / \sqrt{45})}$ results in a z-value of approximately 1.68.

At a Certain University, the Average Cost of Books Was