Previously an organization reported that teenagers spent 45

Previously, an organization reported that teenagers spent 4.5 hours per week, on average, on the phone. The organization thinks that, currently, the mean is higher.

Fifteen randomly chosen teenagers were asked how many hours per week they spend on the phone. The sample mean was 4.75 hours with a sample standard deviation of 2.0.

If you conducted a hypothesis test the null and alternative hypotheses would be:

Note: x ¯ is the sample average, typically refered to has xbar, an x with a horizintal line over it.

Ho: x ¯= 4.75,    Ha: x ¯ > 4.75

Ho: 4.5,        Ha: < 4.5

Ho: = 4.75,    Ha: > 4.75

Ho: = 4.5,            Ha: > 4.5

Solution

Ho: x ¯= 4.75,    Ha: x ¯ > 4.75

NULL: teenagers spent 4.5 hours per week

Alternative: teenagers spent more than 4.5 hours per week