Chapter 10 Smartbook Research Methods in Psychology

Within-subjects design

A single group of subjects is exposed to all levels of independent variable.

What will happen if a subject learns how to perform a task in the first treatment of an experimental study?

His or her performance in later treatments is likely to be better.

Identify an advantage of the matched-groups experimental design.

It allows one to demonstrate a given effect with fewer subjects, thus saving time and money.

Identify the advantages of a within-subjects experimental design.

It can help reduce error variance. It pushes the logic of matching to the limit.

Which of the following statements is true of evenly distributing the effect of the characteristic on which the subjects of an experiment are matched across the treatments in a matched-groups design?

It makes it more likely that any effect of the independent variable will be detected.

Identify the disadvantages of a within-subjects experimental design

It produces carryover effects. It is increasingly demanding on subjects and, thus, leads to subject attrition.

Identify the true statements about a within-subjects experimental design.

It provides the ultimate degree of matching. It eliminates the need for measuring and matching subject variables.

Which of the following is a possible disadvantage of making treatment order an independent variable in a within-subjects experimental design?

It requires a separate group of subjects for every treatment order.

Identify the sources of carryover effects in a within-subjects experimental design.

Learning Habituation Fatigue

_____ experimental designs require a researcher to use somewhat modified versions of the inferential statistics the researcher would use in an unmatched, completely randomized experimental design.

Matched-groups

What are the advantages of the randomized two-group design?

No pretesting or categorization of subjects is necessary. It is simple to carry out. Everything else being equal, it requires relatively few subjects.

Arrange the steps involved in using a matched-groups experimental design in the correct order of occurrence.

Obtain a sample of subjects from the larger population of subjects. Assess the subjects on one or more characteristics that are believed to exert an influence on the dependent measure. Group the subjects whose characteristics match, and distribute them randomly across the experimental groups. Expose participants to their respective levels of the independent variable and record the resulting data. Compare the data from the different groups to determine the effect of the independent variable.

The effect of the characteristic on which the subjects of an experiment are matched in a matched-groups experimental design gets evenly distributed across the treatments because _____.

each of the matched subjects goes into a different group

If subjects go through a period of adaptation, then _____. This produces a carryover effect in a within-subjects experimental study.

earlier results may differ from later results because of the adjustment changes

Random assignment of subjects results in groups of subjects that have been equalized, over the long run, on individual difference factors that contribute to _____.

error variance

The variability among scores caused by variables other than a researcher's independent variables is known as

error variance

Before introducing the treatments in an experimental study, allowing time for subjects to adapt or habituate to the _____ can eliminate carryover from these sources.

experimental conditions

If one wants to assess the effects of several independent variables on a given dependent variable, one should use a _____ experimental design.

factorial

One can deal with the problem of carryover by using a _____ experimental design for one's study.

factorial

In the _____ experimental design, each subject is exposed to every combination of levels of all the factors.

factorial within-subjects

Using the matching strategy on the multigroup designs requires one to _____.

find a similar subject for every treatment group in an experimen

In a higher-order factorial experimental design, a researcher should use at least _____ per group for a reasonable ability to detect the effects of the independent variables.

five subjects

The experimental design that allows one to evaluate a large number of independent variables within a single design is the _____.

fractional factorial design

In a matched-groups experimental designs, the effect of the characteristic on which the subjects were matched gets distributed evenly across the treatments. As a result, this characteristic contributes little to the differences between _____.

group means

Repeated exposure to a stimulus may lead to reduced responsiveness of a subject to that stimulus in a within-subjects experimental design. This reduction is termed _____.

habituation

One way to eliminate practice as a source of confounding in a within-subjects experimental design is to _____.

include practice sessions in which the participants became proficient enough at the task that little further improvement would be expected

A way to deal with the problem of carryover in an experiment is to make treatment order a(n) _____.

independent variable

In single-factor multilevel experimental designs, if the _____ is not a cumulative factor, then the order of treatments is counterbalanced to prevent any carryover effects from confounding the effects of the treatments.

independent variable

In the factorial within-subjects experimental designs, each _____ is referred to as a factor.

independent variable

The single-factor two-level experimental design includes just two levels of a single _____.

independent variable

The term parametric refers to the systematic variation of the amount of the _____ in an experimental design.

independent variable

A(n) _____ is present in a factorial experimental design when the effect of one independent variable changes across the levels of another independent variable.

interaction

Since a within-subjects experimental design is more powerful than an equivalent between-subjects experimental design, one can _____.

use fewer subjects in one's experiment

In the randomized two-group experimental design, one learns about _____.

whether the two groups differed in their responses to an independent variable

If a researcher wishes to assess changes in performance as a function of increasing exposure to the treatment conditions of a study, he or she should use the _____ experimental design.

within-subjects

When the number of available subjects is limited and carryover effects are absent in an experimental study, one should consider using a _____ design.

within-subjects

If one's experimental design has more than about three groups, it is advisable to use a _____.

within-subjects design

In an experimental study, one can effectively eliminate the impact of subject differences on one's dependent variable by adopting a _____.

within-subjects design

In within-subjects experimental designs, the most serious asymmetry in carryover effects occurs when a treatment produces _____.

irreversible changes

A disadvantage of the randomized two-group design is that _____.

it provides limited information about the effect of independent variables

The separate effect of each independent variable on a dependent variable in a factorial experimental design is called a _____.

main effect

A feature of the matched-groups design is that it is an experimental design in which _____.

matched sets of subjects are distributed at random into the groups of an experiment

The need for only two groups makes the _____ relatively economical of time and subjects. Multiple choice question.

matched-pairs experimental approach

The _____ experimental design is used when a single control group is not adequate to rule out alternative explanations of a researcher's results.

multiple control group

When a single control group in an experimental study is not adequate to rule out alternative explanations of a researcher's results, he or she should use the _____.

multiple control group design

In an experimental design, if the probability of error variance producing differences between subject groups is low enough, the results are said to be _____.

statistically significant

An accurate statement about matched-multigroup designs is that one uses these designs to gain control over _____.

subject-related variables that affect one's dependent variable

One of the ways to reduce error variance in an experimental study is by using _____.

subjects matched on characteristics

Making treatment order an independent variable in a within-subjects experimental design requires one to _____.

test subjects under every treatment condition

A problem with extended factorial experimental designs concerns _____.

the number and complexity of the resulting interactions

By convention, a two-factor design that includes two levels of factor A and three levels of factor B would be labeled a _____ factorial design.

2 X 3

If one has to conduct a higher-order factorial experimental study using two factors and five participants per group, one would need to recruit _____ participants.

20

Arrange the steps involved in calculating the main effects of independent variables in factorial experimental designs in the correct order of occurrence

Average Colums Average Rows Compare

Identify the reasons why it is difficult to hold all the extraneous variables constant in an experimental design.

Because the environmental conditions are not absolutely constant Because the behavior of the same subject differs from moment to moment

Which of the following are the similarities between within-subjects and matched-groups experimental designs?

Both designs take advantage of any correlations between subject variables and the dependent variable to improve power. Both designs deal with error variance by attempting to control subject-related factors.

Identify a way to deal with error variance in an experimental design.

By selecting the correct levels of independent variable

Identify a way in which a researcher can estimate the probability with which error variance alone would produce differences between subject groups at least as large as those actually observed in an experimental design.

By subjecting the data to a statistical analysis using inferential statististics

_____ aims to distribute any carryover equally across treatments so that it does not produce differences in treatment means that could be mistaken for an effect of the independent variable.

Counterbalancing

Which of the following designs are frequently used in psychological research to examine the course of processes such as reinforcement, extinction, and fatigue?

Designs that repeatedly sample the dependent variable across time or trials

Between-subjects design

Different groups of subjects are randomly assigned to the levels of independent variable

_____ is the variability among scores caused by variables other than the independent variables present.

Error variance

Identify a case of sensitization as a source of carryover in within-subjects experimental designs.

Exposure to one stimulus can cause subjects to respond more strongly to another stimulus.

Identify the experimental design in which one selects only those levels of the independent variables that specifically test one's hypotheses.

Fractional factorial design

Which experimental design is more than adequate to test one's hypothesis, avoiding the need for a more complex matching design?

Randomized two-group design

Arrange the steps involved in conducting a randomized two-group experiment in the correct order of occurrence. (Place the first step at the top.)

Sample a group of subjects from the general population. Randomly assign the participants from the sample group into two treatment groups. Expose the participants in each treatment group to their treatments and record their responses. Compare the two means to determine whether the two different groups differ. Submit the data to a statistical analysis to assess the reliability of any difference that is found.

Identify the types of experimental designs.

Single-subject design Within-subjects design Between-subjects design

Identify a characteristic of matched-groups experimental designs.

The inferential statistics used in matched designs are less powerful than their unmatched equivalents.

Nonparametric designs

These are used when one manipulates one's independent variable qualitatively.

Parametric designs

These are used when one manipulates one's independent variable quantitatively.

True or false: A within-subjects design is usually a better choice than a matched-groups design if one is concerned about carryover effects in one's experimental study.

This is false. A matched-groups design would be a better choice than a within-subjects design if one is concerned about carryover effects in one's experimental study. Although one loses the economy of having fewer subjects, one preserves the power advantage made possible by matching.

True or false: Adaptive changes as a source of carryover in a within-subjects experimental study does not affect the responsiveness of a subject to a stimulus.

This is false. Adaptive changes may increase responsiveness to a stimulus or decrease responsiveness of a subject.

True or false: One can minimize all sources of carryover present in a within-subjects experimental study.

This is false. One can deal with carryover effects by minimizing or eliminating them. Not all sources of carryover can be minimized in a within-subjects experimental study.

True or false: In cases where subjects differ greatly on characteristics that influence their performances on the dependent measure, the randomized two-group design may help to a great extent to detect a real effect of the independent variable.

This is false. The randomized two-group design may fail to detect a real effect of the independent variable in cases in which subjects differ greatly on characteristics that influence their performances on the dependent measure.

True or false: A principal way to deal with error variance in experimental research is to reduce it as much as possible.

This is true. A principal way to deal with error variance in experimental research is to reduce it as much as possible. It is primarily for this reason that experiments are so often conducted in a laboratory environment, where the researcher can gain strict control over many of the extraneous variables that might otherwise cause error variance.

A way to minimize carryover in habituation, adaptation, and fatigue in an experimental study is to _____.

allow breaks between the treatments

In between-subjects experimental designs, a researcher can reduce any remaining error variance by _____.

assigning subjects to his or her treatment conditions randomly

In an experimental study, it may not be possible to restore subjects to the "naive" state once they learn to perform a task in one treatment. In this case, one should select a _____ approach.

between-subjects

In the context of within-subjects experimental designs, when a previous treatment alters the behavior of subjects observed in a subsequent treatment of a study, __ __occur.

carryover effects

With respect to carryover effects in a within-subjects experimental design, _____ provides every possible ordering of treatments and assigns at least one subject to each ordering.

complete counterbalancing

In order to manipulate one's independent variable, one can get some idea about the levels to include by _____.

conducting a pilot study

A _____ as a source of carryover may emerge when subjects can compare what they receive in one condition to what they receive in another condition in a within-subjects experimental design.

contrast effect

Sam is highly praised for successful performance on one task and poorly reviewed for a subsequent task. He feels underrated in the second task, and starts putting lesser effort in his work. This is an example of _____ as a source of carryover in a within-subjects experimental study.

contrast effect

An advantage of the matched-groups design is that a researcher can _____ that may otherwise obscure the effect of the independent variable under investigation.

control subject variables

The process of assigning various treatments of an experiment in a different order for different subjects is called

counterbalancing

In an experimental design, error variance occurs when differences among subjects and environmental factors affect _____.

dependent variables

Most investigators limit factorial experimental designs to no more than three factors because data resulting from such designs are _____.

difficult to analyze and interpret

If the lines of a graph representing different levels of an independent variable are _____, an interaction may be present.

not parallel

While dealing with carryover effects, the minimum number of subjects required for complete counterbalancing in an experimental study is equal to the _____.

number of different orderings of the treatments

With respect to dealing with carryover effects in a within-subjects experimental design, _____ includes only some of the possible treatment orders.

partial counterbalancing

If the performance of a subject in earlier treatments of a within-subjects experimental design leads to fatigue, then _____.

performance in later treatments may deteriorate

A true statement about the within-subjects experimental design in terms of economizing on subjects is that it _____.

preserves an acceptable degree of reliability

One of the limitations of the _____ experimental design concerns its sensitivity to the effect of the independent variable.

randomized two-group

The matched-pairs experimental design is the matched-groups equivalent to the _____ experimental design.

randomized two-group

If a researcher randomly assigns subjects to two groups, exposes the two groups to different levels of an independent variable, and takes steps to hold extraneous variables constant, the researcher is using a _____.

randomized two-group design

When one uses partial counterbalancing to deal with carryover effects in an experiment, one assumes that _____.

randomly chosen orders will randomly distribute carryover effects among the treatments

A true statement about minimizing carryover effects in a within-subjects experimental design is that it _____.

reduces error variance

A child will show an exaggerated startled response to a sudden noise if he or she had already received a shock in the same situation in _____ as a source of carryover effect in an experiment.

sensitization

In the _____ experimental design, a single group of subjects is exposed to three or more levels of a single independent variable.

single-factor multilevel within-subjects

The simplest form of within-subjects experimental designs is the _____ design.

single-factor two-level