Assignment 5: Single Sample Tests

 1. For each of the following, tell which of the three tests we described in class this week you would use, AND why.

 a. You see an ad for a car that claims they tested it and it got 78 miles to the gallon. You later see an industry report that says for the last year the average miles per gallon for people that owned the car is 75.5 and the SD = 3.7. Is the ad misleading?

 b. In the US 60% of people say they favor the death penalty. In your survey, 550 out of 700 favored the death penalty. You want to see if this is an unusual sample.

 c. In a recent election, the student body president won with 78% of the vote. A sample of people who lived off campus only voted for her at a 71% rate. Is this unusual?

 d. Suppose you sampled 100 in your dorm at Notre dame and gave them a religiosity questionnaire with a possible score of 0-100. The mean score in your dorm is 80 with an SD of 12. You also know that the mean for the whole student body is 60. Are the people in your dorm unusually religious?

 2. Actually compute these tests:

 a. A Random sample of 423 Chinese Americans has finished an average of 12.7 years of education with a Standard Deviation of 1.7. Is this significantly different from the national average of 12.2 years?

 b. Do sociology majors have more fun? Students at ND go to an average of 3.3 parties per month. A random sample of 117 sociology students found an average of 3.8 parties a month with a standard deviation of 0.53.

 c. Suppose the IQ in our class is 110 on the average and there are 30 people in our class. Knowing that the population mean for IQ is 100 and the SD is 15, is our class any smarter than the rest of the population?