PRACTICE QUIZ ANSWERS
MC 1. MULTIPLE CHOICE. Choose the one alternative that best completes the
statement or answers the question.
Solve the problem: A random sample of 56 fluorescent light bulbs has a mean life of 645
hours with a standard deviation of 31 hours. Construct a 95% confidence interval for the
(636.9, 653.1) CORRECT ANSWER
MC 2. MULTIPLE CHOICE
In a recent study of 42 eighth graders, the mean number of hours per week that they
watched television was 19.6 with a standard deviation of 5.8 hours. Find the 98%
confidence interval for the population mean.
(17.5, 21.7) CORRECT ANSWER
SA 3. SHORT ANSWER.
The Marketing analyst of a major e-commerce site claims that the mean time for someone
to checkout an item is at most 5 minutes. Write the null and alternative hypotheses.
MC 4. MULTIPLE CHOICE
Choose the one alternative that best completes the statement or answers the question: The
mean age of bus drivers in Chicago is greater than 51.3 years. If a hypothesis test is