A study conducted by the research institute of America has concluded that the mean number of hours a person spends in their car during a typical week in 1999 was 15 hours. Given that times have changed in the past 20 years in terms of employment rates and public transit, it is reasonable to believe people spend more or less time in their cars every week. Because we can see it going either way, we want to test the null hypothesis that the people spend 15 hours in their car against our alternative hypothesis that people spend a different amount of time in the car in 2019 compared to 1999.

To test this hypothesis, assume we distributed a survey to 100 randomly selected adults in San Antonio and asked them about their driving background. We found the following information:

Sample Statistics:

time spent in a car = 18.3 hours (SD = 11.7)

Use this information to complete ALL steps of hypothesis testing. You should

1. Compute Sample Statistics by finding the obtained Z-score for our sample using z = ( - μ)/se; where se = ???? / √????.

SE =

Z_obtained =

2. Compare our obtained z-score with the critical z-score and determine whether we should reject the null hypothesis:

3. Fully interpret the results in terms of your hypotheses, including the approximate probability our null hypothesis would be correct in a perfect world: