Question

Question 2: The Journal of the American Medical Association reported in 2002 on a study of 1,100 airline passengers who flew from San Francisco to Denver. 515 of these passengers traveled on planes where air was re-circulated, the remaining 585 traveled on planes that did not recirculate air. Of those that did travel on planes where the air was recirculated, 110 reported post-flight respiratory problems. Of those on planes that did not recirculate the air, 108 reported post-flight respiratory problems.

1. (a) Is there a difference in the proportion of passengers who experience post-flight respiratory problems between planes who re-circulate air and planes that do not? State the statistical hypotheses.

2. (b) Carry out the statistical test at a level of significance of 5%.

3. (c) What can you conclude?

4. (d) Interpret the meaning of the P -value you computed, in the context of the data.
   Should you reject the null hypothesis in part (a), compute the 95% confidence interval for the difference in the proportion of passengers experiencing post-flight respiratory problems in planes that recirculate air and planes that do not, pReCirculate − pNoRecirculate.

Answer 1

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