Chapter 10

Which of the following is the most likely disadvantage of a within-subjects design experiment?

It suffers from carryover effects, which is a serious problem.

Dr. Jones conducts a randomized two-group experiment on the effect of a drug on learning. She finds that subjects who receive the drug score more poorly on a memory test than those who do not receive the drug. Which of the following would Dr. Jones be justified in concluding?

It would be dangerous to speculate on the nature of the function relating the independent and dependent variables.

In the _____ design, the number of treatment orders is equal to the number of treatments.

Latin square

In a within-subjects experiment, subjects are required to perform a complex motor task for the dependent variable. You find that they perform better in the second treatment than in the first. You conclude that your independent variable had a significant effect on motor behavior. However, an alternative explanation is that _____ produced a carryover

Learning

Which of the following is effective in dealing with carryover effects in an experiment?

Making treatment order an independent variable

The matched equivalent of a randomized two-group design is the:

Matched-pair design

If you vary the quantity of a drug administered to subjects by using 10 mg, 20 mg, and 40 mg, you are using a _____ design.

Parametric

When you manipulate your independent variable quantitatively, you are using a _____.

Parametric design

In a(n) _____ design, only some of the possible treatment orders are included in a within-subjects experiment.

Partially counterbalanced

In an experiment designed to study the effects of a drug on behavior, participants in the control group received a sugar pill rather than either the active drug or no drug. These participants constitute a:

Placebo control group

In a _____ design, you assign subjects to one of two groups on a purely random basis.

Randomized two-group

An experimental design with more than two levels of a single independent variable is called a _____ design.

Single-factor multigroup

Which of the following is an advantage of a within-subjects experimental design?

The likelihood of detecting the effects of an independent variable is greater than in a between-subjects design.

In an experiment on the effects of alcohol on memory, participants are first tested after drinking a nonalcoholic beverage and then tested again after drinking an alcoholic beverage. This is an example of a _____ design.

Within-subjects

In a matched-groups design, if the matched characteristic does not have much effect on the dependent variable under the conditions of the study, then it results in:

a loss of statistical power that will reduce the ability to detect the effect of the independent variable.

Carryover effects caused by adaptation and habituation can be reduced by:

allowing time for all subjects to adapt or habituate to the experimental conditions.

An advantage of the matched-groups design over the random assignment is that the matched-groups design:

allows you to control subject variables that might otherwise obscure the effect of your independent variable.

Dr. Harris conducts a two-factor experiment where she plots her results on a graph and notices that the lines on the graph are not parallel (which is confirmed when she runs a statistical analysis). This pattern suggests the presence of:

an interaction between two independent variables.

Dr. Franke is conducting an experiment on group decision making. The experiment will run for an entire academic semester. Dr. Franke runs his experimental group at the beginning of the semester and his control group at the end of the semester. The confounding variable here is:

that different groups were run at different times during the semester.

When more than three factors are included in a factorial design, _____.

the interpretation of higher-order interactions becomes increasingly difficult as the number of factors increases

Counterbalanced designs are effective in reducing carryover effects in within-subjects designs if:

the order effects induced by different orders are of the same approximate magnitude.

In a factorial design, the main effects are:

the separate effects of each independent variable on your dependent variable.

In a two-factor factorial experiment, the effect of Factor A at a given level of Factor B is called _____.

the simple effect of Factor A at the given level of Factor B

A serious problem with the within-subjects design is that:

there is a potential for carryover effects.

In a 2 2 2 factorial design, there are:

three main effects and four interactions.

A _____ design includes a single dependent variable.

univariate

Within-subjects designs cope with the problem of error variance by:

using the same subjects in all treatment conditions.

A complete counterbalanced design is most practical in experiments:

with a small number of treatments.

You are interested in studying how airline pilots react in emergency situations. To preserve external validity, you want to use real airline captains. In this case, a within-subjects design would be most desirable because:

you will probably be faced with a limited supply of participants.

A way of reducing error variance is to:

All Of the above

In a single-subject design, _____.

All of the above

Which of the following was not listed in the text as a source of carryover effects in within-subjects designs?

Demand charecteristics

No amount of counterbalancing will eliminate _____ carryover effects.

Differential

The statistical variability among scores caused by the influence of variables other than your independent variable is called _____ variance.

Error

Which of the following is the most likely source of confounding?

Experimenter bias

Subjects in a two-level within-subjects experiment on reaction time respond to 2,000 stimuli in the first condition and then immediately respond to 2,000 more stimuli in the second condition. You notice that the subjects perform more poorly in the second condition than in the first. The confounding variable here is:

Fatigue

Which of the following is true of the within-subjects design?

Fewer subjects are required than in an equivalent between-subjects design.

Identify a true statement about matched-groups experimental designs.

Matching with a large number of groups becomes unwieldy because it is difficult to find subjects with equivalent scores on the variables to be matched.

All other things being equal, compared to the between-subjects design, the within-subjects design is:

More powerful

Often in studies that look at the effects of drugs on behavior, it is found that a participant's behavior can be altered if he or she believes a drug was taken. To test for this possibility, you would use a:

Multiple control group design

A drawback to the completely within-subjects factorial design is that:

as the number of factors increases, so does the number of treatments that the subjects must go through, making the design cumbersome and complex for subjects.

In the context of types of experimental designs, each treatment is administered to a different group of subjects in a _____.

between-subjects design

A viable alternative to counterbalancing is to:

make treatment order an independent variable in your experiment.

Which of the following statements is true of confounding variables in an experiment?

They damage the internal validity of an experiment.

Analysis of your data with inferential statistics:

helps you decide whether your results are an effect of your independent variable or simply the result of error variance.

A factorial design always has more than one:

independent variable.

An experimental design with two or more dependent variables is termed _____ design.

multivariate

Which of the following is a way of dealing with the problem of error variance?

Increasing the effectiveness of the independent variable

Manipulating your independent variable qualitatively results in a _____.

Nonparametric design

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

Within-subjects

According to the text, a disadvantage of a within-subjects design is that:

each subject must spend more time in your experiment and thus may become fatigued.

The best way to avoid confounding variables in an experiment is to:

plan carefully how your independent variables are to be executed.

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

single-factor two-level

A design including a placebo control group is used to detect:

the effect of a participant's belief that he or she has received a drug.

In cases where you want to assess changes in performance as a function of increasing exposure to treatment conditions, the most appropriate design is a _____.

within-subjects design

The matched-groups design is most useful when:

you suspect that some subject characteristics are strongly correlated with your independent variable.

_____ occur(s) when a previous treatment alters the observed behavior in subsequent treatments.

Carryover effects

___ provides every possible ordering of treatments and assigns at least one subject to each ordering.

Complete counterbalancing

According to the text, the confounding in the original "Pepsi Challenge" could have been avoided by:

Counterbalancing

One assigns the various treatments of an experiment in a different order for different subjects in _____.

Counterbalancing

If the effect of one independent variable changes over the levels of a second, a(n) _____ is present.

Interaction

The most serious form of carryover effects occurs when your experimental treatment produces:

Irreversible changes

Although you can use matching with a single-factor multigroup design, it may not be advisable because:

It becomes difficult to find three or more subjects that can be matched.

An advantage of a factorial design is that you can identify:

both the main effects of independent variables and any interactions between independent variables.

One way to reduce the impact of carryover caused by practice effects is to:

give subjects equivalent practice sessions to bring them all up to the same level of performance.

With complete counterbalancing, order effects are dealt with by:

having treatment conditions presented in every possible order.

A factorial design with more than two independent variables is called a _____ design.

higher-order factorial

An advantage of the randomized two-group design is that it:

is simple to carryout, and data are easy to analyze.

The presence of error variance

makes it difficult to determine if your independent variable was effective.

In a matched-groups design, after selecting a sample of subjects, you:

match pairs of subjects on some measured characteristic (e.g., intelligence), and randomly assign one member of each pair across experimental groups.

Making treatment order an independent variable allows you to:

measure the amount of carryover and take it into account in future experiments.

An advantage of a within-subjects design over a matched-pairs between-subjects design is that:

measuring subject characteristics is unnecessary in a within-subjects design.

Carryover effects are:

potentially problematic only in within-subjects designs.

A drawback of the randomized two-group design is that it:

provides a limited amount of information about the effect of an independent variable.

A key assumption behind partial counterbalancing in a within-subjects experiment is that:

randomly chosen treatment orders will randomly distribute carryover effects among the treatments.

Within-subjects designs are most useful when:

subject differences contribute heavily to variation in the dependent variable.

A drawback of making treatment order an independent variable is that:

subjects must be tested under every treatment order, resulting in a complex and demanding experiment.