1) A person read that the average number of hours an adult sleeps on Friday night to Saturday morning was 7.2 hours. The researcher feels that college students do not sleep 7.2 hours on average. The researcher randomly selected 15 students and found that on average they slept 8.3 hours. The standard deviation of the sample is 1.2 hours. At \(\alpha=0.05\), is there enough evidence to say that college students do not sleep 7.2 hours on average?

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2) A U.S. Web Usage Snapshot indicated a monthly average of 36 Internet visits a particular website per user from home. A random sample of 24 Internet users yielded a sample mean of 42.1 visits with a standard deviation of 5.3. At the 0.01 level of significance,can it be concluded that this differs from the national average?

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3) The director of a medical hospital feels that her surgeons perform fewer operations per year than the national average of 211. She selected a random sample of 15 surgeons and found that the mean number of operations they performed was 208.8. The standard deviation of the sample was 3.8. Is there enough evidence to support the director’s feelings at \(\alpha=0.10\)? Would the null hypothesis be rejected at \(\alpha=0.01\)?