1. The EPA is suing the city of Rochester for noncompliance with carbon monoxide standards. Specifically, the EPA wants to show that the mean level of carbon monoxide is higher than 4.9 parts per million. To test this, what is the null hypothesis?

2. An engineer wants to show, on average, that application of paint made with a new formula dries and is ready for the next coat in less than 30 min. To test this, what is the alternative hypothesis?

3. Suppose a theory suggests that the mean of single-digit random numbers is 4.5, with a standard deviation of 2.87. If you wanted to run an experiment to test this theory, by generating random numbers and finding the mean, what would the alternative hypothesis be?

4. Many people sleep late on the weekend to make up for "short nights" during the workweek. The Better Sleep Council reports that at most 61% get more than 7 hours of sleep per night on the weekend. A independent study gathered a random sample of 350 adults found that 235 had more than 7 hours of sleep each night of a given weekend. We want to use this sample to test the Better Sleep Council's findings. What is the null hypothesis?