Question

PROBLEM 3. Researchers wanted to determine whether drivers are significantly distracted while driving when using a cell phone or talking to a passenger in the car. In a study involving 60 drivers, 20 drivers were randomly assigned to drive while using a cell phone, 20 drivers were assigned to drive while talking to a passenger, and the remaining drivers drove alone in the car. Part of the study involved asking drivers to exit the freeway at a particular exit. In the study, 8 phone users missed the exit, while only 3 talking to a passenger missed the exit, and no driver who drove alone missed the exit. 1. Explain why this study is an experiment. 2. Explain the purpose of having a group of drivers who drove alone. How is this group called? 3. Name 3 possible confounding variables in this experiment.

Answer 1

1.

In an experiment investigators apply treatments to experimental units (people, animals, plots of land, etc.) and then proceed to observe the effect of the treatments on the experimental units.

In the given example, treatments like using cell phone, talking to passenger while driving were applied and the effect of the treatments on number of the drivers (exprimental units) missing the exit measured. So, the study was an experiment.

2.

The purpose of having a group of the drivers who drove alone is to establish a baseline to compare the changes in the treatment groups. It attempts to reduce the effect of confounding independent variables. The group is called Control Group.

3.

3 possible confounding variables in this experiment may be -

1. Driving Skills - An amateur driver may miss the exit irrespective of whether he use cell phone, talk or drive alone.

2. Age - An old age driver may have greater chance of missing the exit irrespective of whether he use cell phone, talk or drive alone.

3. Technology - Cell phone users may use navigation apps to help him correctly exit the freeway with higher chance than driving alone.