Test whether there is difference between two population mean.
Paramedics in a large city say they need more staff at night because they get more emergency calls then. A random sample of 7 nights showed that the paramedics received the following numbers of emergency calls during the night: 72, 81, 85, 80, 88 82, 56. A sample of 7 different days showed that the paramedics received the following numbers of emergency calls during the day: 65, 54, 81, 67, 75, 83, 79.
1. State the random variables and means in words.
2. Use a 1 percent level of significance to test the claim that there are more calls during the night than in the day.
3. Find a 99% confidence interval for the difference in the mean number of calls between night and day.
4. State the assumptions for the test in terms of the problem.