In the month of August of a given year, there were 13,318 canceled flights out of 531,035 total flights in the US. In that month, Chicago O'Hare airport had 1,558 flights out of 29,949 of its total flights canceled. We want to look at whether or not O'Hare airport's performance is any different than the performance of the nation's airports as a whole at a 5% level of significance.

1. State the null hypothesis. (Make sure that your null hypothesis is clear and unambiguous.)

2. At a 5% level of significance, does the performance of Chicago O'Hare airport differ from the nation as a whole? How did you achieve this conclusion? Explain.

3. What is the upper limit of the 95% confidence interval for the proportion of canceled flights at O'Hare?