CHAPTER 10
GROUP-COMPARISON RESEARCH
TEACHING ACTIVITIES FOR CHAPTER 10
Activity 1. Independent and dependent variables.
We have found that many students have trouble distinguishing between the concepts of independent variables
and dependent variables. These concepts are critical to understanding quantitative research designs that involve
causal relationships: group comparison research, correlational research, and experiments. Therefore, it is important
to help students develop a clear grasp of these concepts.
One way to develop students’ understanding is to explain that independent variables are hypothesized causes
and dependent variables are hypothesized effects. Then give students some examples, perhaps on an overhead, to
test their understanding, e.g.,
a. Does multiple vaccination increase the likelihood of autism?
b. Do students who perform poorly in middle school tend to perform poorly in high school?
Activity 2. Using group-comparison methodology to study causal relationships.
As a homework assignment, you can ask students to specify some feature of students, teachers, or schools that
interest them. For example, a student might be interested in a school’s emotional climate. Ask students to
hypothesize at least two factors that influence variations in this variable (e.g., schools with a positive climate versus
schools with a negative climate). Finally, ask them to specify what groups they could study and what independent
Activity 3. Analysis and evaluation of the article reprint.
You can ask students to read the reprinted article about teachers’ beliefs at the end of Chapter 10 and evaluate it
using the criteria in Appendix 3 and those specified on pages 244-245. In class, you can call on students to state
what they consider strengths and weaknesses of the study. Also, you can ask them to form small groups in which
they discuss the practical significance of the study’s findings.
MULTIPLE-CHOICE TEST ITEMS FOR CHAPTER 10
1. In research, the causal variable in a cause-and-effect relationship is called the
a. dependent variable.
b. independent variable.
c. y variable.
d. fixed variable.
2. In research, the effect variable in a cause-and-effect relationship is called the
a. dependent variable.
b. independent variable.
c. x variable.
d. fixed variable.
3. Group-comparison research
a. can demonstrate cause-and-effect relationships as well as experiments can.
b. can demonstrate cause-and-effect relationships better than experiments can.
c. can demonstrate cause-and-effect relationships less well than experiments can.
d. cannot be used to study cause-and-effect relationships.
4. In a group-comparison research study, if the comparison groups are designed to differ on an
independent variable, the study will focus on
a. describing their differences on this variable.
b. explaining why they differ on this variable.
c. determining whether this variable can be manipulated.
d. predicting how the groups will differ on variables that occur at a later point in time.
5. A primary reason for choosing a group-comparison research design is that
a. the researchers are unable to manipulate the dependent variable.
b. the researchers are unable to manipulate the independent variable.
c. the statistical tools that are available for this design are more powerful than for an experimental
design.
d. All of the above.
6. Group-comparison research studies can include
a. one independent variable and multiple dependent variables.
b. multiple independent variables and one dependent variable.
c. multiple independent variables and multiple dependent variables.
d. multiple independent variables and one fixed variable.
7. In group-comparison research,
a. the comparison groups should represent different values of the independent variable, but be
identical in all other respects.
b. it does not matter if the comparison groups differ on independent variables other than the one that
is being investigated.
c. it does not matter whether the comparison groups are randomly selected from defined populations.
d. the comparison groups ideally should be identical on at least three fixed variables.
8. If comparison groups differ on other variables besides the independent variable, a statistical approach for
equating the groups on these other variables is
a. the t test.
b. the use of measures of central tendency.
c. analysis of variance.
d. analysis of covariance.
9. The practical significance of observed differences on an independent variable or dependent variable in
a group-comparison study can be determined by
a. effect sizes.
b. t tests.
c. analysis of variance.
d. measures of central tendency.
10. A single analysis of variance
a. can determine only the effect of one independent variable on a dependent variable.
b. can determine only the effect of two independent variables on a dependent variable.
c. can determine the effects of multiple independent variables on a dependent variable and also their
interaction effects.
d. can determine only the interaction effects of multiple independent variables on a dependent
variable.
11. Nonparametric tests of statistical significance should be used in group-comparison research studies if
a. the comparison groups differ on variables other than the independent variable.
b. the assumptions underlying parametric tests of statistical significance are violated.
c. interaction effects of multiple independent variables are of interest.
d. All of the above.
SHORT-ANSWER TEST ITEMS FOR CHAPTER 10
1. Explain the terms (a) independent variable and (b) dependent variable as used in group-comparison
research.
2. Explain why it is important to select groups in group–comparison research that are closely comparable except
on the independent variable.
3. Suppose that a researcher wanted to study whether military service has a positive effect on the problem-solving
ability of young adults. Why would group-comparison research be the best approach for investigating this
problem?
4. A researcher selected two groups of fourth-grade students: those who were rated by observers as highly active
on the playground during recess and those who were rated as exhibiting a low level of activity. The researcher
then obtained teachers’ ratings of each student’s level of participation during classroom activity. (The teachers
were unaware of the playground observations or their results.) Students rated as highly active on the
playground were found to have significantly higher ratings for classroom participation than students rated low
in playground activity. Give one causal interpretation of these findings that might be correct.
CHAPTER 10
GROUP-COMPARISON RESEARCH
Multiple-Choice Test Items
Short-Answer Test Items