Citrus Rental is a popular car rental agency that has a history of having too few cars available, so that its available cars are overdriven. The mean monthly mileage over the years for Citrus cars has been about 1600 miles per month. ? Recently, though, Citrus purchased thousands of new cars, and the company claims that the average mileage of its cars is now less than in the past. To test this, a random sample of 16 recent mileages of Citrus cars was taken. The mean of these 16 mileages was 1517 miles per month, and the standard deviation was 233 miles per month. Assume that the population of recent monthly mileages of Citrus cars is normally distributed. At the 0.05 level of significance, can it be concluded that the mean recent monthly mileage, μ, of Citrus cars is less than 1600 miles per month? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary, consult a list of formulas.) (a) State the null hypothesis H and the alternative hypothesis H₁. H₂ :O H₁ :0 (b) Determine the type of test statistic to use. (Choose one) ▼ (c) Find the value of the test statistic. (Round to three or more decimal places.) (d) Find the critical value. (Round to three or more decimal places.) (e) At the 0.05 level of significance, can it be concluded that the mean recent monthly mileage of Citrus cars is less than 1600 miles per month? OYes ONO H Ix O S X 00 0#0 O0

In the 1980's it was believed that congenital abnormalities affected about 5.4% of the nation's children. Some people believe that an increase in the chemicals in the environment has led to an increase in the number of abnormalities. A recent study examined 400 randomly selected children and found that 29 of them showed signs of an abnormality. Does this provide evidence that the risk of congenital abnormalities has increase? Use a 0.05 to make your decision. What is the resulting test statistics?

A psychological study wants to analyze the relationship between anxiety and binge drinking; a questionnaire for anxiety and questionnaire for binge drinking is administered to each subject. What would be a good statistical test to test the hypothesis?

The sample data here is the cholesterol levels for 10 men diagnosed with high cholesterol. The first row represents levels from 10 men who did not use the drug and the second row from 10 different men who did use the drug. If we want to test the claim that the mean level for all men who use the drug is less than the mean for all men who do not use it, what is the appropriate alternative hypothesis?    The mean cholesterol level of males who take the medicine is higher than the mean cholesterol levels of men who do not take it.       There is a significant difference between males who use the medicine and men who do not use the drug in terms of mean cholesterol levels.       The mean cholesterol level of males who take the medicine is lower than the mean cholesterol levels of men who do not take it.       There is no significant difference between males who use the medicine and men who do not use the drug in terms of mean cholesterol levels.