Stats Chapter 11 Test Questions
and Answers All Correct
A study will be conducted to investigate whether there is a difference in pain relief for
two brands of headache pills, N and P. Participants will be randomly assigned to one of
two groups. One group will take pill N when they experience a headache, and the other
group will take pill P when they experience a headache. Each participant will record the
number of minutes it takes until relief from the headache is felt. The mean number of
minutes will be calculated for each group.
Which of the following is the appropriate test for the study? - Answer-NOT
A matched-pairs t-test for a mean difference
If the customer rolls the dice and rents a second movie every Thursday for 20
consecutive weeks, what is the total amount that the customer would expect to pay for
these second movies? - Answer-$9.40
A spinner made for a game of chance has 8 equally likely spaces. Alfonso records the
result of a sample of 400 spins. Alfonso decides to calculate a chi-square test statistic
for a goodness-of-fit test to see whether the spinner is fair. Which of the following is the
appropriate null hypothesis? - Answer-Ho:p1=0.125,p2=0.125,p3=0.125,p4=0.125,p5
=0.125,p6=0.125,p7=0.125,p8=0.125
regular equal sign
Which of the following is not a condition for a chi-square goodness-of-fit test? - Answer-
The distribution of the sample should be approximately normal.
Let X represent the number on the face that lands up when a fair six-sided number cube
is tossed. The expected value of X is 3.5, and the standard deviation of X is
approximately 1.708. Two fair six-sided number cubes will be tossed, and the numbers
appearing on the faces that land up will be added. Which of the following values is
closest to the standard deviation of the resulting sum? - Answer-2.415
Which of the following chi-square distributions has the smallest number of degrees of
freedom? - Answer-hump all the way to the left
Two siblings, Alice and Sean, are both convinced that they are faster than the other at
solving a puzzle cube. They recorded the length of time it took them to solve the cube
18 times each during a one-month period. Then each calculated the mean amount of
time and standard deviation, in minutes, for their times. Let μAμA equal the mean time it
took Alice to solve the puzzle cube and μSμSequal the mean time it took Sean. Which
of the following are the appropriate null and alternative hypotheses to test for a
difference in time for the siblings to solve the cube? - Answer-NOT
,Ho:x‾A−x‾S=0Ho:xA−xS=0
Ha:x‾A−x‾S>0Ha:xA−xS>0
An airline claims that the mean flight time between City X and City Y is 38 minutes. After
taking many flights, a local business group believes that the claim is unrealistic and that
the actual mean flight time is greater than 38 minutes. If the group conducts a study to
investigate its belief, which of the following hypotheses should be tested? - Answer-
NOT
H0: x̅ = 38, versus Ha : x̅ > 38
NOT
H0: x̅ = 38, versus Ha : x̅ < 38
A chi-square test was conducted to investigate whether there is an association between
a person's favorite flavor of ice cream and their favorite toppings. Each of 200 randomly
selected customers at an ice cream parlor was asked to pick their favorite flavor from
vanilla, chocolate, chocolate chip, or none of these. They were also asked to pick their
favorite topping from chocolate sauce, peanuts, crumbled cookies, crushed candies, or
none of these. The hypothesis test had a test statistic of 24.97 with an associated p-
value of 0.015. If the significance level of the test was α=0.05α=0.05, which of the
following is the correct decision for this hypothesis test? - Answer-There is convincing
statistical evidence to suggest an association between favorite ice cream flavor and
favorite topping.
A large factory that builds machines has three shifts, one that starts at 4:00 A.M., one
that starts at noon, and one that starts at 8:00 P.M. The manager of the factory wanted
to know whether there is an association between an employee's work experience (less
than five years with the company, between five and twenty years with the company,
over twenty years with the company) and the time of the employee's shift. The manager
selected a random sample of 125 employees and classified employees by their shift
time and work experience. Which of the following is an appropriate pair of hypotheses
for the manager to use? - Answer-Ho:Work experience is independent of the time of an
employee's shift.
Ha:Ha:Work experience is dependent on the time of an employee's shift.
polling randomly selected responding stuff - Answer-NOT
two fractions, bottom of each is a square.
Researchers for a company that manufactures batteries want to test the hypothesis that
the mean battery life of their new battery is greater than the known mean battery life of
their older version. The researchers selected random samples of 32 of the new
batteries, subjected the batteries to continuous use, and determined the mean and
standard deviation of the battery lives in the sample.
Which of the following is an appropriate test for the researchers' hypothesis? - Answer-
A one-sample t-test for a population mean
, A polling organization uses random digit dialing of registered voters in a county to
gauge the voters' opinions about a ballot initiative to increase taxes that would pay for a
new county park. The polling organization will investigate whether there are differences
in how voters respond based on the highest level of education completed. The phone
survey asked the voters contacted whether they approve or disapprove of the tax
increase. The voters were also asked to indicate their highest level of education
completed: high school, bachelor's degree, or master's degree.
Which of the following is the appropriate test to investigate whether there is an
association between opinion about the ballot initiative and highest level of education
completed? - Answer-A chi-square test of independence
A national health study reported that the proportion of students with elevated blood
pressure is 0.15. The principal of a local high school believes that the proportion of
students in the school with elevated blood pressure is greater than 0.15. If a large
random sample is used, which of the following is the most appropriate test to investigate
the principal's belief? - Answer-A z-test for a proportion
Ecologists conducted a study to investigate the potential ecological impact of golf
courses. Investigators monitored the reproductive success of bluebirds in birdhouses at
nine golf courses and ten similar birdhouses at nongolf sites. Data on nests in
birdhouses occupied only by bluebirds are shown in the table.
Observed Number of Nests per Birdhouse by Location
0 nests1 nest2 or 3 nestsTotalGolf3042880Nongolf405822120Total7010030200
If the proportions of nests occupied is the same for golf and nongolf sites, what would
be the expected count of birdhouses with 1 nest in nongolf locations? - Answer-60
A fisheries biologist collected a random sample of fish from a lake and conducted a chi-
square goodness-of-fit test to see if the distribution of fish changed over time. The table
below shows the distribution of fish that were put into the lake when it was originally
stocked.
Fish TypeTroutBassPerchSunfishCatfishPercent25%25%20%15%15%
The biologist found evidence to reject the null hypothesis in favor of the alternative
hypothesis. Which of the following represents the alternative hypothesis of the test? -
Answer-At least one of the fish proportions is different than the corresponding
proportion when the lake was originally stocked.
A factory produces bags of rubber bands. A bag of rubber bands has five different sizes:
extra large (XL), large (L), medium (M), small (S), and extra small (XS). A quality control
specialist collects a random sample of 450 rubber bands from the bagging machine and
calculates a chi-square goodness-of-fit test to see if the frequencies for each size in the
sample match the hypothesized distribution. The quality control specialist will test his
sample against the following null hypothesis
Ho:pXL=0.10,pL=0.20,pM=0.40,pS=0.20,pXS=0.10Ho:pXL=0.10,pL=0.20,pM=0.40,pS
=0.20,pXS=0.10
How many medium rubber bands are expected in the random sample of 450 rubber
bands? - Answer-180
