1. You test the claim that the mean gas mileage of all cars of a certain make is less than28 miles per gallon (mpg). You perform this test at the 0.05 significance level. What is the probability of a Type I error for this test?
2. Larry claims that more than a quarter of all his email is spam. In a random sample of 40 of his emails, 14 of them are spam. Test his claim at the 0.10 significance level.
3. What is the same proportion of spam in his email?
4. What is the test statistic?
5. What is the P-value of the test statistic?
6. Do you reject the null-hypothesis or fail to reject it?
7. We want to test the claim that people are taller in the morning than in the evening. Morning height and evening height were measured for 32 randomly selected adults and the difference (morning height) (evening height) for each adult was recorded. The mean difference was 0.22 cm with a standard deviation of 0.41 cm. Use this information to test the claim that on average people are taller in the morning than in the evening. Test this claim at the 0.05 significance level.
8. What is the test statistic? Round to 2 decimal places
9. What is the P-value of the test statistic? Round to 4 places
10. It is widely accepted that people are a little taller in the morning than at night. Here we perform a test on how big the difference is. In a sample of 39 adults, the mean difference between morning height and evening height was 5.5 millimeters (mm) with a standard deviation of 1.6 mm. Test the claim that, on average, people are more than 5 mm taller in the morning than at night. Test this claim at the 0.10 significance level.
11. Claim is that the mean difference is more than 5mm. What type of test is this?
12. What is the test statistic? Round to 2 places
13. What is the p-value of the test statistic? Round to 4 places
14. Do you reject or fail to reject the null hypothesis?