The director of transportation for a local city is putting t

The director of transportation for a local city is putting together a new bus schedule. As part of this process the director needs to determine the average amount of time it takes the bus to travel from the stop on 9th street to the stop on Whorley Avenue. The director took a sample of 30 instances that the bus traveled this route. The resulting data can be found in Statcrunch by clicking here. Use Statcrunch to calculate a 95% confidence interval for the true average amount of time it takes the bus to travel this route. Which of the following are true for this situation? Select one or more:

1. We believe the average amount of time for the bus to travel the route is between 15.5 and 16.4 minutes.

2. We believe the average amount of time for the bus to travel the route is between 15.5 and 16.7 minutes.

3. We believe the average amount of time for the bus to travel the route is between 15.5 and 17.7 minutes.

4. We believe the average amount of time for the bus to travel the route is between 17.9 and 19.5 minutes.

5. We believe the average amount of time for the bus to travel the route is between 18.4 and 20.0 minutes.

6. For our confidence interval to be valid we must assume the sample is random and representative of the population of interest.

7. This procedure would be appropriate even if the population is skewed since the procedure based on the t-distribution will be robust because of the sample size.

8. We must know the population would be very symmetric since the procedure based on the t-distribution will NOT be robust because of the sample size.

Solution

The Answer is option 4 and option 6