The article "More Communities Banning 'Television on a Stick'" describes an ongoing controversy over the
distraction caused by digital billboards along highways. One study mentioned in the newspaper article is
described in "Effects of Advertising Billboards During Simulated Driving." In this study, 48 people made a
9 km drive in a driving simulator. Drivers were instructed to change lanes according to roadside lane change
signs. Some of the lane changes occurred near digital billboards. What was displayed on the digital billboard
changed once during the time that the billboard was visible by the driver to simulate the changing digital
billboards that appear along highways. Data from this study supported the theory that the time required to
respond to road signs was greater when digital billboards were present.

(a) What is the population of interest?
the 48 people that participated in the driving simulation
inexperienced drivers in the U.S.
people that drive along highways with digital billboards
all drivers in the U.S.
drivers who are distracted by digital billboards

(b) What claim was tested?
Drivers are more likely to have an automobile accident when digital billboards are present.
Drivers are less likely to have an automobile accident when digital billboards are present.
The time required to respond to road signs increases when digital billboards are present.
Drivers are more distracted by digital billboards when the display changes.
The time required to respond to road signs decreases when digital billboards are present.

(c) What additional information would help you decide if it is reasonable to generalize the conclusions of
this study to the population of interest? (Select all that apply.)
the month in which the data was collected
the opinions of the researchers on digital billboards
the names of the researchers
the names of the drivers
if the drivers were randomly selected

(d) Assuming that the people who participated in the study are representative of the population of
interest, do you think that the risk of an incorrect conclusion would have been lower, about the same,
or higher if 100 people had participated instead of 48?

lower
about the same
higher