Answers to Concepts and Exercises

CHAPTER 2

Research in Psychology

ANSWERS TO CONCEPTS AND EXERCISES

Research Methods

1.j is the answer.Experiments are usually tests of hypotheses based on descriptive and correlational data. Correlations, even very strong ones, do not demonstrate causation. Scientists do experiments to determine whether there is a causative relationship between strongly correlated variables. (see Correlation and Correlation Coefficients)

2.e is the answer.Once scientists decide to do an experiment, they must identify and define the independent and dependent variables. (see Experiments: Exploring Cause and Effect)

3.a is the answer.Sometimes an operational definition is needed to specify how one or more of the variables will be measured. (see Critical Thinking and Scientific Research)

4.i is the answer.Experiments have two groups: experimental and control. Subjects should be assigned randomly to these groups to reduce the effect of random variables. (see Experiments: Exploring Cause and Effect)

5.g is the answer.In an experiment, researchers systematically manipulate the independent variable. (see Experiments: Exploring Cause and Effect)

6.b is the answer.Then they measure the dependent variable. (see Experiments: Exploring Cause and Effect)

7.f is the answer.Measurements of the dependent variable are compared for the experimental and control groups. (see Experiments: Exploring Cause and Effect)

8.k is the answer.Statistical methods determine whether the differences between the dependent variables in the control and experimental groups occurred by chance. (see Inferential Statistics)

Choose Your Method

1.b is the answer.Experiments indicate causation. The question here is whether sleep loss causes changes in problem-solving ability. None of the other methods listed shows causation. (see Experiments: Exploring Cause and Effect)

2.d is the answer.This is a rare phenomenon, examination of which requires that a great deal of information be gathered about one person (the child). Researchers would conduct a case study in such circumstances. (see Case Studies: Taking a Closer Look)

3.c is the answer.Naturalistic observation would provide the data necessary to answer this question. The researcher would observe the attention span of five-year-old children at the playground, rather than asking them about it. (see Naturalistic Observation: Watching Behavior)

4.a is the answer.Surveys are used to find out people’s opinions. (see Surveys: Looking at the Big Picture)