- Private colleges and universities rely on money contributed byindividuals and corporations for their operating expenses. Much ofthis money is invested in a fund called an endowment, and thecollege spends only the interest earned by the fund. A recentsurvey of eight private colleges in the United States revealed thefollowing endowments (in millions of dollars): 60.2, 47.0, 235.1,490.0,
22.6, 177.5, 95.4,and 220.0. Summary statistics yield x = 180.975 ands = 143.042. Calculate a 99%
confidence intervalfor the mean endowment of all private colleges in the UnitedStates. Note that s is sample standarddeviation.
A) 180.975 ± 181.387                                                           B) 180.975 ± 169.672
C) 180.975 ± 176.955                                                           D) 180.975 ± 189.173
2) An educator wanted to look at thestudy habits of university students. As part of the research, datawas collected for three variables - the amount of time (in hoursper week) spent studying, the amount of time (in hours per week)spent playing video games and the GPA - for a sample of 20 maleuniversity students. As part of the research, a 95% confidenceinterval for the average GPA of all male university students wascalculated to be: (2.95, 3.10). The researcher claimed that theaverage GPA of all male students exceeded 2.94. Using theconfidence interval supplied above, how do you respond to thisclaim?
A) We are 95%confident that the researcher is correct.
B) We are 95%confident that the researcher is incorrect.
C) We are 100%confident that the researcher is incorrect.
D) We cannot makeany statement regarding the average GPA of male university studentsat the 95% confidence level.
3) A retiredstatistician was interested in determining the average cost of a$200,000.00 term life insurance policy for a 60-year-old malenon-smoker. He randomly sampled 65 subjects
(60-year-old malenon-smokers) and constructed the following 95 percent confidenceinterval for the mean cost of the term life insurance: ($850.00,$1050.00). State the appropriate interpretation for this confidenceinterval. Note that all answers begin with \"We are 95 percentconfidence that…\"
A) The term lifeinsurance cost of the retired statistician's insurance policy fallsbetween $850.00 and $1050.00
B) The average termlife insurance cost for sampled 65 subjects falls between $850.00and
$1050.00
C) The term lifeinsurance cost for all 60-year-old male non-smokers' insurancepolicies falls
between $850.00 and $1050.00
D) The average termlife insurance costs for all 60 -year-old male non-smokers fallsbetween
$850.00 and$1050.00
4) How many tissuesshould a package of tissues contain? Researchers have determinedthat a person uses an average of 41 tissues during a cold. Supposea random sample of 10,000 people yielded the following data on thenumber of tissues used during a cold: x = 35, s =18. Identify the null and
alternativehypothesis for a test to determine if the mean number of tissuesused during a cold is
as claimed.
A) H0:μ > 41 vs. Ha: μ ≤ 41                                              B) H0: μ = 41 vs. Ha: μ ≠41
C) H0:μ = 41 vs. Ha: μ < 41                                             D) H0: μ = 41 vs. Ha: μ >41
5) A local eat-inpizza restaurant wants to investigate the possibility of startingto deliver pizzas. The owner of the store has determined that homedelivery will be successful only if the average time spent on adelivery does not exceed 37 minutes (no morwe). The owner hasrandomly selected 15 customers
and delivered pizzasto their homes. What hypotheses should the owner test todemonstrate that the pizza delivery will not be successful?
A) H0:μ = 37 vs. Ha: μ < 37                                              B) H0: μ < 37 vs. Ha: μ =37
C) H0:μ ≤ 37 vs. Ha: μ > 37                                              D) H0: μ = 37 vs. Ha: μ ≠37
6) Researchers haveclaimed that the average number of headaches per student during asemester of Statistics is 11. In a sample of n = 16students the mean is 12 headaches with a deviation of 2.4. Which ofthe following represent the null and alternative hypothesesnecessary to test the students' belief?
A) H0:μ = 11 vs. Ha: μ > 11                                              B) H0: μ = 11 vs. Ha: μ <11
C) H0:μ < 11 vs. Ha: μ = 11                                             D) H0: μ = 11 vs. Ha: μ ≠11
