The American Academy of Pediatrics (AAP) recommends that kids 2-5 years old watch no more than (on average) 1.6 hours a day of quality programming. A researcher selected a sample of 101 kids in the neighborhood and asked their parents how many hours per day they allow their kids watching TV. She found out that the kids in the sample spend on average 1.75 hours watching TV with a standard deviation of 0.85. Do the kids in this neighborhood spend more hours watching TV than what recommended by the AAP? Is this a two-tailed or one-tailed test? (Test the hypothesis at 95% level).

Answer 1

Hypotheses:

H0: µ ≤ 1.6
H1: µ > 1.6

Test is one-tailed (H1 shows a specific direction).

Use a one-sample z-test:
z = (1.75 - 1.6)/(0.85/√101)

Finish the calculation, then determine whether or not to reject the null hypothesis (H0). If the null is rejected, you can conclude µ > 1.6 hours.