AP Statistics Hypothesis Testing and Confidence Intervals Take Home Test 40 Points. Name Due Date:

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1 AP Statistics Hypothesis Testing and Confidence Intervals Take Home Test 40 Points Name Due Date: For each problem, do the appropriate test and complete all sections. Calculators are allowed but you must show all important statistics found. Conclusions must be made in a sentence form that is appropriate for the problem situation. Test: 1. A local chamber of commerce claims that the mean family income in a city is $12,250. An economist suspects otherwise and runs a hypothesis test using a sample of 135 families and finds a mean of $11,500 with a standard deviation of $3,180. Should the $12,250 claim be rejected at a 5% level? Find the 95% confidence interval for mean family income Stu Schwartz

2 2. A union spokesman claims that 75% of union members will support a strike if their basic demands are not met. A company spokesman believes the true percentage is lower and runs a hypothesis test at the 10% significance level. What is the conclusion if 87 of 125 union members say they will strike? What is the 90% confidence interval for the percentage of members who say they will strike? Stu Schwartz

3 3. A store manager wishes to determine whether there is a significant difference between two trucking firms with regards to the handling of egg cartons. In a simple random sample of 200 cartons on firm A s truck, there was an average of 0.7 broken eggs per carton with a standard deviation of 0.31, while a sample of 300 cartons on firm B s truck showed an average of broken eggs per carton with a standard deviation of Is the difference between the averages significant at the 5% level? Stu Schwartz

4 4. Suppose that early in an election campaign, a telephone poll of 800 registered voters shows that 460 favor a particular candidate. Just before election day, a second poll shows that 520 of 1,000 registered voters now favor that candidate. At the 2% significance level, is there sufficient evidence that the candidate s popularity has decreased? Give a 99% confidence interval for the difference in the percentage favoring that candidate in the two polls Stu Schwartz

5 5. Does a particular drug slow reaction time? If so, the government might require a warning label concerning driving a car while taking the medication. An SRS of 30 people are tested before and after taking the drug and their reaction times (in seconds) to a driving situation requiring a quick reaction time are noted. Is there evidence at the 5% level that the reaction time for people using the drug is greater than those who do not? Calculate the 95% confidence interval of the difference in reaction time. The data is below. Test: Person Before After Person Before After Person Before After Stu Schwartz