We look at a random sample of 1000 United flights in the month of December comparing...
We look at a random sample of 1000 United flights in the month of December comparing the actual arrival time to the scheduled arrival time. Computer output of the descriptive statistics for the difference in actual and expected arrival time of these 1000 flights are shown below.
| N | Mean | StDev | SE Mean | Min | Q1 | Median | Q3 | Max |
| 1000 | 9.59 | 41.5 | 1.31 | -35 | -12 | 0 | 15 | 447 |
(a) What is the sample mean difference in actual and expected arrival times? What is the standard deviation of the differences?
(b) Can we proceed using the t distribution to build a confidence interval for this mean?
(c) Regardless of your answer to part (b), use the summary statistics to compute a 95% confidence interval for the average difference in actual and scheduled arrival times on United flights in December.
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