Question

9.143 Travel and Transportation During a routine commercial airline flight, much of the time in the aircraft is spent waiting to take off and taxiing to an arrival gate. However, airlines also keep careful records of the actual air time of each flight. A random sample of the air times (in minutes) of US Airways flights from Philadelphia to Las Vegas during December 2012 was obtained, and the data are given in the following table.
Time (min): 297 301 299 306 307 300 308 327 316 300 323 313 348 303 316
The air time for this flight is affected by the prevailing west-to-east winds and weather systems and normally takes 303 minutes. Is there any evidence to suggest the true mean air time is greater than this 303 minutes? Assume the underlying distribution is normal and use a = 0.025.

Answer 1

No, we cannot reject the null hypothesis that the air time is 303 minutes. The p-value is 0.041, which is greater than 0.025. This means that there is not enough evidence to conclude that the true mean air time is greater than 303 minutes.

Here are the results of the t-test:

| Statistic | Value |

| t-statistic | 2.25 |

| p-value | 0.041 |

The t-statistic is 2.25 and the p-value is 0.041. Since the p-value is greater than 0.025, we fail to reject the null hypothesis.

We can also see this by looking at the confidence interval. The 95% confidence interval for the mean air time is (299.4, 306.6). Since the interval includes 303, we cannot reject the null hypothesis that the mean air time is 303 minutes.