Mrs. Emma 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 1% significance level.

What is the test value (z) of the problem? (Round off to three decimal places)