Question

Suppose that we want to test the claim that the mean of a population is greater than 20. Also suppose that the population standard deviation is known to be 7. A sample of 49 measurements reveals a mean of 22. What is the value of the test statistic?

Answer 1

$z=\frac{x−μ}{σ/\sqrt{n}}=\frac{22-20}{7/\sqrt{49}}=2.00$