Question

A study claims that on average, male high school students spend at least 3.39 hours a day playing video games with a standard deviation of 2.05 hours. A random sample of 30 teenagers were surveyed and the results showed that these teenagers spend 4.12 hours a day playing video games.

What is the null hypothesis for the given problem?

Answer 1

The following null and alternative hypotheses need to be tested:

$H_0:\mu\ge3.39$

$H_1:\mu<3.39$

This corresponds to a left-tailed test, for which a z-test for one mean, with known population standard deviation will be used.