Exam 7: The Experimental Research Strategy

A researcher decides to use only participants that weigh between 150 and 160 pounds in an experiment comparing two treatment conditions. For this study, what method is being used to control participant weight?

The possibility that an extraneous variable can become a confounding variable is eliminated completely by holding it constant.

In an experiment, any variable that varies systematically with the treatment conditions and might influence the participants' scores is called a(n) ____ variable.

A researcher intends to compare two different treatment conditions. Participants for the first treatment are selected and tested early in the school semester, and participants for the second treatment are selected and tested late in the semester. In this study, the time-of-testing represents a confounding variable.

Describe and differentiate the three methods to control extraneous variables.

The specific treatment conditions that are used in an experiment are called the ____.

Simulation and field studies are used to increase the external validity of experiments.

Researchers often use simulation experiments in an attempt to obtain the ____ of an experiment and still keep much of the ____ of research conducted in the real world.

Which characteristic is necessary for an extraneous variable to become a confounding variable?

In an experiment, participants are usually assigned to treatments using random assignment. The reason for using random assignment is ____.

In an experiment comparing two treatments, the researcher assigns participants to treatment conditions so that each condition has 10 adults with college degrees and 10 adults with high-school diplomas only. For this study, what method is being used to control participant education level?

What is the primary goal for randomly assigning participants to treatment conditions in an experiment?

In an experiment, the purpose for manipulating the independent variable is to help ____.

A recent study reports that the more sexual content that adolescents watch on TV, the more likely they were to engage in sexual behaviors. However, it is unclear whether the sexual content on TV leads to sexual behavior or whether sexual behavior leads to a preference for sexual content on TV. This is an example of the third-variable problem.

All experiments must have either a no-treatment control group or a placebo control group.

Describe one situation where a manipulation check might be appropriate and explain what the manipulation check is intended to accomplish.

In an experiment examining how caffeine influences people's perceptions of their own efficiency, one group of participants is given decaf coffee before they make their judgments. This would be classified as a placebo control condition.

Dr. Ramos is interested in studying how indoor temperature can influence people's sleep quality during the summer. A sample of 100 households is selected in which the residents keep their houses at 76 degrees during the summer. The residents wear a monitoring device that measures their sleep cycles for several nights to get baseline readings. Then, 50 of the homes are randomly assigned to the warm temperature condition in which the residents agree to keep their houses at 82 degrees Fahrenheit. In the other 50 houses, the residents agree to keep their houses at 70 degrees. For several nights, Dr. Ramos collects the sleep data for the people living in the houses to see how the residents' sleep patterns have changed. Assuming that the study allows people to use as many or as few blankets as they like, number of blankets would be a(n) ____ variable in the experiment.

Manipulation checks are particularly important for simulations to ensure that the simulation is effective.

A researcher is performing an experiment to determine whether eating chocolate can improve memory. Measurements of memory in this experiment would be the ____ variable.