Question 23
A 95% confidence interval has been created for the number of days that it takes to get a package from Amazon using
free shipping. The printout showing the confidence interval is shown below. Which one of the statements below is true
(assuming the confidence interval is correct).
95% of the packages are delivered between 10.2 and 12.7 days.
It always takes more than 10 days for a package to arrive.
It takes on average more than 11 days for a package to arrive.
On average it takes more than 10 days for a package to arrive.
Question 24
GE is concerned when they found reports claiming that 38% of consumers believe that the light in the refrigerator is still
on when the door is closed. It was determined that 98 out of the 232 consumers polled believe that the light stays on.
How would you characterize the claim that 38% of consumers believe that the light in the refrigerator is still on when
the door is closed (assuming the confidence interval shown below is correct.)
Question 25
A soft drink company asked a group of teenagers and a group of retirees if they drank one or more energy drinks in the
last 24 hours. The results and the confidence interval are shown below.
Assuming the confidence interval is correct, which one of the following statements is true.
Teenagers are more likely to have drank an energy drink in the last 24 hours.
Retirees are more likely to have drank an energy drink in the last 24 hours.
Retirees and teenagers are equally likely to have drank an energy drink in the last 24 hours.
It is unclear if retirees or teenagers are more likely to have drank an energy drink in the last 24 hours.
Question 26
A group is interested in the average delivery time of packages from Amazon that use the free supersaver shipping. What
can you conclude about the mean population delivery time from this printout at the .05 level of significance?
Question #26 continued…….
On average, packages take 10 days.
On average, packages take less than 10 days.
On average, packages take more than 13.33 days.
The results are inconclusive.
On average, packages take more than 10 days.
Question 27
The NHS conducted a study to compare the systolic blood pressure for Type A and Type B individuals. Based on the
printout below, what can you conclude about the difference in systolic blood pressure in Type A and Type B populations
at the .10 level of significance?
Type As have lower blood pressure on average.
There is no difference between the blood pressure of Type As and Type Bs on average.
Type Bs have lower blood pressure on average.
The difference in these populations is .2.823
The results are inconclusive.
Question 28
There has been some controversy as to how long ACME’s and XYZ’s servo motors last. An experiment was conducted on
43 motors taken from each company. What can you conclude about these populations from the following printouts at
the .01 level of significance?
Question #28 continued……
ACME motors last 4.434 hours on average longer than XYZ motors.
ACME motors last longer on average.
XYZ motors last longer on average
Both companies’ motors last the same amount of time.
The results are inconclusive.
Question 29
ACME has been accused of producing poor quality motors. In response to these accusations, ACME claims that over half
of their motors last more than 100 hours. A random sample of their motors were tested and the results of the statistical
analysis is shown below. Can you prove ACME’s claim at the .05 level of significance? The following proportions are the
percent of motors that lasted more than 100 hours.
Over 50% of ACME’s motors last 100 hours.
50% of ACME’s motors last 100 hours.
Less than 50% of ACME’s motors last 100 hours.
The results are inconclusive.
Question 30
Best Buy conducted a study to see if they could prove their claim that men were more likely to buy service contracts
than women. What can you conclude about their claim at the .09 level of significance based on the printout below?
Men are more likely to buy service contracts.
Men and women are equally likely to buy service contracts.
Women are more likely to buy service contracts.
The results are inconclusive.
Question 31
How well does the number of beers a student drinks predict his or her blood alcohol content? Seventeen student
volunteers at The University of South Carolina drank a randomly assigned number of cans of beer. Thirty minutes later a
police officer measured their blood alcohol content (BAC). The data were used to determine a regression equation which
relates Y=Blood Alcohol Content to X=Number of Beers Consumed. A partial listing of the data and an EXCEL output
summarizing the regression output are provided below.
Which one of the following statements is true? (see next page)
The r-square for this problem is very low.
The confidence interval for the number of drinks indicates that additional drink will raise a student’s BAC
by .0607.
there is no proven relationship between number of drinks and BAC.
We expect on average that an additional drink will increase a student’s BAC by between .0534 and .0681.
Question 32
A study was conducted for an MBA program to determine what factors seemed to be related to how well the student
performed in the Quantitative Methods. The data collected was the average study hours per week, GMAT score, years of
work experience and the student’s final grade average Quantitative Methods. The regression printout using this data is
shown below. Which one of the following statements is true about the population of MBA students?
See answer options on the next page……..
Hours studying, GMAT and work experience are all positively related to the grade average in Quantitative
Methods.
Hours studying and work experience are positively related to the grade average in Quantitative Methods
while GMAT is negatively related.
None of the variables are related to the grade average in Quantitative Methods.
Only hours studying and work experience are related to the grade average in Quantitative Methods.
Question 33
A study was conducted for the PMBA program to determine what factors seemed to be related to how well the student
performed in the Quantitative Methods. The data collected was the average study hours per week, GMAT score, years of
work experience and the student’s final grade average Quantitative Methods. A sample of the data used and the
regression printout is shown below. Taking into account the confidence interval for years of work experience, which one
of the statements below is true?
There may be no advantage to work experience on average.
An additional work experience will decrease a student’s grade in Quantitative Methods.
A student with some work experience, on average, will get between 1.16 and 1.67 higher than a student
that has no work experience.
It appears that each additional year of work experience will increase a student’s expected grade average by
over 1 point.
Question 34
A study was conducted to determine the value of having a graduate degree for employees at ACME. The data used for
this study included the years of experience, age, whether or not the employee had a graduate degree (if they did the
graduate degree variable was set to 1, otherwise it was set to 0) and their salary in thousands of dollars.A sample of the
data and the regression printout are shown below. What is your estimate of how much an employee that had 10 years
of work experience, was 40 years old and did not have a graduate degree will earn?
15.25
41.25
37.62
44.57
