From the book

Credit Card Debt It has been reported that the average credit card debt for college seniors is $3262. The student senate at a large university feels that their seniors have a debt much less than this, so it conducts a study of 50 randomly selected seniors and finds that the average debt is $2995, and the population standard deviation is $1100. With a significance level of 0.05, is the student senate correct?


Moviegoers The average “moviegoer” sees 8.5 movies a year. A moviegoer is defined as a person who sees at least one movie in a theater in a 12-month period. A random sample of 40 moviegoers from a large university revealed that the average number of movies seen per person was 9.6. The population standard deviation is 3.2 movies. At the 0.05 level of significance, can it be concluded that this represents a difference from the national average?


Cost of Building a Home According to the National Association of Home Builders, the average cost of building a home in the Northeast is $117.91 per square foot. A random sample of 36 new homes indicated that the mean cost was $122.57 and the standard deviation was $20. Can it be concluded that the mean cost differs from $117.91, using the 0.10 level of significance?  Find the P-value for the test.


Salaries of Ph.D. Students Full-time Ph.D. students receive an average salary of $12,837 according to the U.S. Department of Education. The dean of graduate studies at a large state university feels that Ph.D. students in his state earn more than this. He surveys 44 randomly selected students and finds their average salary is $14,445, and the population standard deviation is $1500. With an alpha of 0.05, is the dean correct?  Find the P-value for the test.


Soft Drink Consumption A researcher claims that the yearly consumption of soft drinks per person is 55 gallons. In a sample of 50  randomly selected people, the mean of the yearly consumption was 56.3 gallons. The standard deviation of the population is 3.5 gallons. Find the P-value for the test. On the basis of the P-value, is the researcher’s claim valid?