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% level of significance to test the claim that there are more calls during the night than in the day.