Chapter 8: Experimental Design

The term ________ refers to the degree to which your research design evaluates the hypotheses that it was intended to evaluate.
1. internal validity
2. external validity
3. internal consistency
4. reliability
In an experiment, internal validity means that:
1. showing changes in your independent variable caused observed changes in your dependent variable
2. most extraneous variables have been identified and controlled
3. showing changes in your criterion variable relate only to changes in your predictor variable
4. none of the above
Internal validity is threatened by:
1. running your experiment under highly artificial conditions
2. the operation of extraneous, uncontrolled variables
3. the presence of quasi-independent variables in your study
4. choosing the wrong strategy to answer your questions
To make sure that participants in all conditions of an experiment are equivalent, the researcher may:
1. match the participant
2. use a repeated measures design
3. randomly assign a sufficient number of participants to the conditions
4. all of the above
Which of the following is a factor affecting the internal validity of a study.
1. participants becoming fatigued
2. changes in the calibrations of the instruments used to measure behavior
3. biased selection of participants
4. all of the above
A design in which different participants are randomly assigned to the various conditions in the experiment is a ________ design.
1. single-subject
2. between-subjects
3. within-subjects
4. matched groups
The statistical variability among scores caused by the influence of variables other than your independent variable is called ________ variance.
1. systematic
2. extraneous
3. random
4. error
The presence of error variance:
1. makes it difficult to determine if your independent variable was effective
2. makes it easier to determine if your independent variable was effective
3. increases the internal validity of an experiment
4. increases the external validity of an experiment
In a matched groups design, after selecting a sample of participants, you:
1. randomly assign participants to your conditions
2. select only the most intelligent participants for inclusion in your research
3. match pairs of participants on some measured characteristic (e.g., weight), then randomly assign one member of each pair to the experimental group and the other to the control group
4. none of the above
An advantage of the matched groups design over random assignment is that the matched groups design:
1. allows you to control participant variables that might otherwise attenuate the effect of your independent variable
2. requires fewer participants
3. uses more participants, which increases the sensitivity of the experiment
4. totally eliminates error variance
A source of confounding is:
1. not randomly assigning participants to conditions in the experiment
2. experimenter bias
3. poorly conceived or executed independent variables
4. all of the above
Dr. Metiva is conducting an experiment on group decision making. The experiment will run for an entire semester. Dr. Metiva runs his experimental group at the beginning of the semester and his control group at the end of the semester. The confounding variable is:
1. that different groups were run at different times during the semester
2. not including more than one control group
3. choosing to run his experiment at an academic institution
4. none of the above
A researcher investigated the effect of weather on college students' study habits. On a sunny day, the researcher sat in the quad and recorded the number of minutes of studying per student. The researcher found that the mean number of minutes of studying was 39.8. What kind of study is this?
1. a one-group pretest-posttest
2. a true experimental design
3. a random group design
4. a one-shot case study
What is the crucial element missing in the above design?
1. an experimental group
2. a control group
3. an independent variable
4. sunshine
To control for order effects in a repeated measures design, you should use:
1. counterbalancing techniques
2. an independent groups design
3. a reversal design
4. a long time interval between conditions

Chapter 8: Experimental Design

Choose the best answer for each question.