Mrs Reyes wants to test if her students in Basic Calculus

Question

Mrs Reyes wants to test if her students in Basic Calculus spend less than 30 minutes per day on homework. A random sample of 64 students shows that they spend an average of 24.5 minutes per day on homework. Assume that the population standard deviation is 15.3 minutes and that the test is to be made at the 5% significance level.

What is the critical value of z? Round your answers to 3 decimal places.

Answer 1

This is a one-sided test. For P(Z <= z) = .05, z = -1.645; this is the critical value.

Note that the test statistic is

z= (24.5 - 30)/(15.3/sqrt(64)) =-2.876

As this value is less than the critical value, we reject the null hypothesis in favor of the alternative that students study less than 30 minutes per day,