Questions

In Module 7, we've learned about several tests for the difference of two means, which allow us to compare two averages.

First, carry out a hypothesis test for the difference of the average flight arrival delay between Alaska Airlines (AS) and Southwest Airlines (WN).

(1) Write out the null and alternative statements, plus the level of significance you'll be using

(2) test statistic (showing work by hand or reference the Excel commands you used), and

(3) p-value clearly. Include necessary screenshots or tables.

(4) Explain the test result in a complete sentence. For example, "because the p-value is (large/small), I (fail to reject/reject) the null hypothesis that American Airlines and Alaska Airlines have the same average arrival delay. In everyday terms, this means ______________."

(5) Explain why the test above is a test comparing independent (rather than matched) means. Note that this test is not a Test of Independence, as the Test of Independence is for categorical data.

(6) How would we calculate a test of matched means between Alaska and Southwest? What would it mean for those flights to be "matched"?

(7) Do you think both these tests (the one you performed and the hypothetical 'matched test') are reasonable? Fair? Why or why not?

AS ARR DELAY WN ARR DELAY 4 -13 20 18 -9 -17 12 -8 -17 -21 24 -2 -13 -22 -1 -36 -13 -11 -17 -19 8 -17 -6 -14 -14 7 -19 -12 -25 -18 -26 -18 -2 -6 -35 -6 -11 -11AS ARR DELAY WN ARR DELAY -8 -15 -17 -19 -8 -5 -21 24 -14 -16 -10 -12 -18 -15 -7 -12 -5 -13 -19 13 3 -7 -12 -14 -14 -13 -4 86 -18 -4 -9 -14 3 -19 -8 -11 -12 0 -21 4 -11 -20 8 -9 -12 -9 8 15 -22 -6 -6 -4 -12 -22 -14 6 -12 -10 -22 -24AS ARR DELAY WN ARR DELAY -4 -23 -21 -17 -22 -7 -5 -17 7 -15 -15 -13 -14 -2 16 -20 -12 -20 -23 -17 -24 6 -12 47 -23 -17 -39 -25 -13 -18 0 -15 -20 5 -13 22 -24 -11 -6 19 -23 -18 -17 -15 -9AS ARR DELAY WN ARR DELAY -35 -9 -8 0 -14 -7 -7 -12 -19 -23 -14 -16 -13 -19 2 8 6 -22 -12 -10 -39 29 -20 -18