Statistics ..

*Open your data in Excel or Statgraphics and answer the following in complete sentences.

1) Step 1 of Hypothesis Test: Write your hypothesis: you might want to start, “I’m testing the hypothesis that the average delay of a flight departing from Oregon airports is less than __________ minutes.”

2) Set your significance level: alpha = ____%.

3) Step 2 of Hypothesis Test: Calculate the test statistic from your 30 flights. Choose 30 rows at random (it’s fine to use the same random 30 rows you picked last week). The formula for the test statistic is given in the lecture slides. Is your test statistic a Z-score or t-score?

Hint 1: If you use sample standard deviation based on the 30 selected flights, your test statistic would be a t-score. If you somehow compute the population standard deviation based on all flights in this spreadsheet, your test statistic would be a z-score.

              Hint 2: If you’re using Word, Insert > Equation will make your life easier as you show your work!

4) Step 4 of Hypothesis Test: what’s your conclusion for this test? In other words, would you be able to conclude whether the average delay of a flight departing from Oregon flights is less than _______ minutes.

Hint 3: Use either the critical value approach or p-value approach. If you decide to use the critical value approach, what’s the critical value for this test? If you’re using the p-value approach, calculate the p-value using your 30 selected flights.

5) Repeat (3) and (4), but test the null hypothesis that half of flights are on Southwest airlines. Again, be sure to show your work clearly!

            Hint 4: remember a hypothesis test for the proportion uses a different equation than a hypothesis test for an average!