Deck 9: Basic Between-Subjects Designs

Question 1

Introduction Researchers always assign subjects to only one treatment condition in ____ designs.

A)between-subjects
B)ex post facto
C)quasi-experimental
D)within-subjects

Answer 1

between-subjects

Question 2

Introduction An experimental design is analogous to a building's

A)floor plan.
B)function.
C)materials.
D)address.

Answer 2

floor plan.

Question 3

Introduction All of these help determine the design of an experiment except

A)the number of independent variables.
B)the number of levels for each independent variable.
C)the scale of measurement used to measure the dependent variable.
D)whether the same or different subjects are run in each treatment condition.

Answer 3

the scale of measurement used to measure the dependent variable.

Question 4

Selecting and Recruiting Subjects You shouldn't ask your friends to participate in your study because they may

A)be low in representativeness.
B)be more sensitive to your subtle cues than strangers.
C)feel obliged to participate.
D)all of these

Question 5

Selecting and Recruiting Subjects When the independent variable creates larger group differences on the dependent variable than we would see if we randomly assigned subjects to groups and only measured them, this demonstrates

A)a large effect size.
B)statistical significance.
C)the experiment's external validity.
D)the experiment's internal validity.

Question 6

Introduction Carlie randomly assigned subjects to either walk 30 minutes a day/three times a week or 45 minutes a day/two times a week and then measured their resting heart rates at the end of two months.Which design was this?

A)between-subjects
B)matched groups
C)multiple independent groups
D)within-subjects

Question 7

Selecting and Recruiting Subjects A sample's representativeness affects

A)external validity.
B)internal validity.
C)statistical power.
D)the experimental design.

Question 8

A researcher would like to match subjects on weight for an experiment on weight control.The weights of each subject in the sample are shown in the table below.Match them into pairs and form one experimental and one control group by using random assignment.Carry out the procedure using precision matching, range matching, and rank-ordered matching.

Question 9

Selecting and Recruiting Subjects Researchers obtain large samples to

A)allow them to use parametric statistics.
B)increase internal validity.
C)increase the effect size of the independent variable.
D)observe the full range of behaviors on the dependent variable.

Question 10

Referring back to question 10, how did the outcomes of precision, range, and rank-ordered matching differ?
The three matching procedures differed in how well they controlled group weight: precision matching (mean difference = 0), range matching (mean difference = 1 pound), and rank-ordered matching (mean difference = 3.5 pounds).They also differed in the number of pairs formed: precision matching (3), range matching (7), and rank-ordered matching (8).
What are the pros and cons of using each procedure?
Precision matching provides the best control over an extraneous subject variable since group scores are identical (pro), but discards the most data (con).
Range matching allows an experimenter to balance control over an extraneous subject variable against the number of scores discarded (pro), but usually discards more scores than rank-ordered matching (con).

Question 11

Introduction Ashton studied the effect of wearing single-strap and double-strap backpacks on shoulder muscle contraction.He tested the same subjects in both single-strap and double-strap conditions to control individual differences in trapezius muscle activity.This study employed a ____ design.

A)between-subjects
B)matched groups
C)multiple independent groups
D)within-subjects

Question 12

Introduction What does "between" subjects mean in a between-subjects experiment?

A)experimenters compare the performance of different groups on the dependent variable
B)experimenters measure a different dependent variable in each treatment condition
C)experimenters provide different demand characteristics in each treatment condition
D)experimenters randomly assign subjects to treatment conditions

Question 13

Selecting and Recruiting Subjects Since Andrew only had 3 days to collect experimental data, he obtained a convenience sample of students eating lunch in the cafeteria.Nonprobability sampling worried him because of risk to his experiment's

A)effect size.
B)external validity.
C)internal validity.
D)statistical power.

Question 14

People who have known each other for a long time may communicate better than people who have known each other for a short time.Imagine you are carrying out the study suggested in question 6.All your subjects know each other, but for varying lengths of time.How can you make sure that the length of time that subjects have known each other will not be a confounding variable in your study?
You can use the control technique of elimination and only use strangers.However, if you intend to generalize the experimental findings to people who know each other, you need to distribute this subject variable across the treatment conditions instead.You can accomplish this with either a two independent groups design or two matched groups design.

Question 15

Selecting and Recruiting Subjects When you want to increase your chance of detecting an effect, you should

A)decrease the number of levels of the independent variable.
B)increase the number of subjects in each condition.
C)use a two independent groups design.
D)use an experimental group-control group design.

Question 16

Selecting and Recruiting Subjects Small samples are adequate when

A)individuals in the population are very different from one another on the dependent variable.
B)individuals in the population are very similar to one another on the dependent variable.
C)researchers employ a matched group design.
D)the estimated effect size is small.

Question 17

Selecting and Recruiting Subjects Increasing the sample size

A)decreases confounding.
B)increases effect size.
C)increases internal validity.
D)increases statistical power.

Question 18

Selecting and Recruiting Subjects When there is a statistically significant difference between two treatment groups, we know that

A)extraneous variables did not confound the study.
B)random assignment created groups that were identical on the dependent variable before the researcher manipulated the independent variable.
C)the effect size of the independent variable is very large.
D)the independent variable produced group differences on the dependent variable that are larger than we would expect due to chance.

Question 19

Introduction All of these are specified by an experimental design except

A)the experimental hypothesis.
B)the number of independent variables.
C)the number of levels for each independent variable.
D)whether the same or different subjects are run in each treatment condition.

Question 20

Introduction The design of an experiment is mainly determined by the

A)dependent variable.
B)experimental hypothesis.
C)independent variable.
D)number of levels of the independent variable(s).

Question 21

Selecting and Recruiting Subjects As the number of subjects assigned to treatment conditions increases,

A)the ability to detect small effects increases.
B)the need for a control group decreases.
C)the need to match subjects increases.
D)the risk of confounding increases.

Question 22

Two Independent Groups When we use random assignment in an experiment, we guarantee that

A)every subject in our sample has an equal chance of being placed in any of the treatment conditions.
B)every subject in the population has an equal chance of being selected for the experiment.
C)the treatment groups are identical on potentially confounding extraneous variables.
D)treatment order is randomized to prevent order effects.

Question 23

Two Independent Groups Jason wanted to see if the dogs in his tracking class would complete a tracking course more rapidly if their owners administered larger rewards when they finished.He randomly assigned dogs to groups that received one, two, or three cubes of cheddar cheese as reward and measured the time it took each group to complete the course over five trials.This experiment did not have

A)a control condition.
B)a dependent variable.
C)an experimental manipulation.
D)an independent variable.

Question 24

Selecting and Recruiting Subjects Researchers use statistical procedures for all of these reasons except

A)to determine whether group differences are statistically significant.
B)to determine the minimum number of subjects needed for each treatment group.
C)to estimate effect size.
D)to select an appropriate experimental design.

Question 25

Two Independent Groups We use a control group in an experiment to

A)measure the dependent variable without the experimental manipulation.
B)prevent confounding by extraneous variables.
C)protect the external validity of the experiment.
D)test the validity of the experimental manipulation.

Question 26

Selecting and Recruiting Subjects You should use ____ subjects per condition to detect a strong treatment effect.

A)5-10
B)10-20
C)20-30
D)30-40

Question 27

Two Independent Groups If we do not randomly assign subjects to treatment conditions,

A)confounding may occur.
B)we will gain external validity.
C)the sample selected may be biased.
D)we will not be able to estimate effect size.

Question 28

Two Independent Groups Weiss (1972) criticized Brady's (1958) "executive monkey" study for its

A)biased sample of subjects.
B)confounding by selection threat.
C)confounding by subject mortality.
D)lack of a control group.

Question 29

Selecting and Recruiting Subjects A researcher should ____ to estimate the minimum number of subjects needed for each treatment group.

A)calculate actual effect size
B)consult a power chart
C)consult a table of random numbers
D)measure the dependent variable's fluctuation

Question 30

Two Independent Groups Brady's (1958) study of ulcers in monkeys compared "executive monkeys" who could prevent shock by hitting a button at least once every 20 seconds and "nonexecutive monkeys" who had no control over the shocks and received the same number of shocks as the executive monkeys to which they were yoked.Which design did Brady use?

A)experimental group-control group
B)multiple independent groups
C)two experimental groups
D)two matched groups

Question 31

Two Independent Groups Random selection of subjects is to ____ as random assignment of subjects to conditions is to

A)confounding; external validity.
B)external validity; internal validity.
C)internal validity; external validity.
D)selection threat; biased sampling.

Question 32

Two Independent Groups In which design do we randomly assign subjects to participate in one of two treatment conditions?

A)two independent groups
B)two matched groups
C)multiple independent groups
D)within-subjects

Question 33

Two Independent Groups
Homer randomly assigned subjects to rate the attractiveness of job candidates with either an obvious facial piercing (experimental condition) or no facial piercing (control condition).Which experimental design did he use?

A)independent groups
B)matched groups
C)multiple independent groups
D)within-subjects

Question 34

Selecting and Recruiting Subjects What information does an experimenter need to use a power chart?

A)estimated effect size
B)number of subjects assigned to each treatment condition
C)the dependent variable's fluctuation
D)whether the study uses an independent groups design or matched groups design

Question 35

Selecting and Recruiting Subjects As a rule of thumb, you should assign at least ___ subjects to each treatment group.

A)5
B)10
C)20
D)45

Question 36

Selecting and Recruiting Subjects If we anticipate large individual differences in subject performance on the dependent variable, we should

A)decrease the number of levels of the independent variable.
B)increase the number of subjects in each condition.
C)use a two independent groups design.
D)use an experimental group-control group design.

Question 37

Two Independent Groups In Kelley's (1950) classic study of the effects of people's expectations on their impressions of others, he gave Introductory Psychology students written descriptions of a guest lecturer before he came to class.Kelley handed out the descriptions at random.Half the students were told the visitor was a "warm" person and half were told he was "cold." After the visitor led a 20-minute class discussion, students rated the lecturer.Which design did Kelley use?

A)experimental group-control group
B)multiple independent groups
C)two independent groups
D)two matched groups

Question 38

Two Independent Groups A "no-treatment" condition in an experiment, which measures how subjects ordinarily perform on the dependent measure, is called the

A)control group.
B)criterion group.
C)experimental group.
D)reference group.

Question 39

Selecting and Recruiting Subjects You may require ____ subjects per condition to detect a weak treatment effect.

A)5-10
B)10-20
C)20-30
D)30-40

Question 40

Selecting and Recruiting Subjects Significant differences between treatment groups are more difficult to detect when

A)members of the population resemble one another on the dependent variable.
B)researchers select subjects using nonprobability sampling.
C)researchers assign a small number of subjects to each treatment condition.
D)the effect size of the independent variable is large.

Question 41

Multiple Groups Santana designed an experiment with four treatment conditions.If she has 20 subjects and decides to assign an equal number of subjects to each condition using block randomization, how many treatment blocks can she complete?

A)2
B)4
C)5
D)10

Question 42

Two Matched Groups Which matching procedure sometimes creates groups with unacceptably large differences on the matching variable?

A)interval matching
B)precision matching
C)range matching
D)rank-ordered matching

Question 43

Two Independent Groups The most serious dilemma posed by waiting-list control conditions in medical and psychotherapy research is that

A)waiting-list controls deny treatment to patients who need it.
B)waiting-list controls lack the credibility of conventional treatments.
C)waiting-list controls possess low external validity.
D)waiting-list controls suffer from high subject mortality.

Question 44

Two Matched Groups Researchers will always create treatment groups of equal size if they use ____ to randomly assign subjects to treatment conditions.

A)a random number table
B)across subjects counterbalancing
C)block randomization
D)subject-by-subject counterbalancing

Question 45

Two Matched Groups Which matching procedure usually discards the most data?

A)interval matching
B)precision matching
C)range matching
D)rank-ordered matching

Question 46

Two Matched Groups Alex matched subjects with adjacent locus of control scores.She used ____ matching.

A)interval
B)precision
C)range
D)rank-ordered

Question 47

Two Matched Groups If the matching variable is not highly correlated with the dependent variable,

A)less powerful statistical tests must be used to analyze the data.
B)the effect size will be inflated.
C)the chances of detecting the effect of the experimental manipulation may be reduced.
D)this will result in statistical regression threat.

Question 48

Two Matched Groups Which of these designs does the best job of controlling extraneous subject variables?

A)experimental group-control group
B)multiple independent groups
C)two experimental groups
D)two matched groups

Question 49

Two Independent Groups In psychotherapy research, ____ are often used as control groups.

A)conventional therapy conditions
B)no-treatment conditions
C)placebo conditions
D)waiting-list conditions

Question 50

Two Matched Groups Dexter formed matched pairs when systolic blood pressures fell within 5 mm Hg.Which form of matching did he use?

A)interval matching
B)precision matching
C)range matching
D)rank-ordered matching

Question 51

Two Independent Groups All of these statements accurately describe random assignment except:

A)Random assignment always produces comparable groups.
B)Random assignment can be performed using a table of random numbers.
C)Random assignment helps control some systematic differences between subjects.
D)Random assignment is an important precaution when using a two-group design.

Question 52

Two Matched Groups In a two matched groups design, the matching variable should be highly correlated with the ____ variable.

A)dependent
B)extraneous
C)independent
D)manipulated

Question 53

Two Matched Groups Will created matched pairs of subjects with identical weights in a study comparing the effectiveness of low-carbohydrate and Mediterranean diets in reducing triglycerides.He used ____ matching.

A)interval
B)precision
C)range
D)rank-ordered

Question 54

Two Matched Groups Matching is invaluable to researchers because it

A)eliminates the need for a control group.
B)increases the chance of detecting the effect of the experimental manipulation.
C)produces a normal distribution of scores.
D)reduces the number of scores that must be discarded.

Question 55

Two Matched Groups Critics have challenged the internal validity of Brady's (1958) study of ulcers in monkeys.Select the design that allows us to compare "executive" and "nonexecutive" monkeys and prevents selection threat.

A)experimental group-control group design
B)multiple groups design
C)two experimental groups design
D)two matched groups design

Question 56

Two Matched Groups In Jason's study of the effect of the magnitude of reward, he randomly assigned dogs to groups that received one, two, or three cubes of cheddar cheese as reward and measured the time it took each group to complete a tracking course over five trials.Which design did he use?

A)experimental group-control group
B)multiple independent groups
C)two experimental groups
D)two matched groups

Question 57

Two Independent Groups Which experimental design raises the fewest ethical concerns in drug research that involves actual patients?

A)comparing a new drug against a standard treatment
B)experimental group-control group design
C)placebo control
D)waiting list control

Question 58

Two Matched Groups Matching procedures are especially useful when we have small numbers of subjects because

A)matching increases the external validity of our experiment.
B)matching produces a normal distribution of scores.
C)random assignment can only be used when there are 20 subjects per group.
D)random assignment may not produce similar groups.

Question 59

Two Matched Groups The ____ design is the most commonly used multiple groups design.

A)multiple baseline
B)multiple independent groups
C)multiple matched groups
D)multiple within-subjects

Question 60

Two Matched Groups Which matching procedure consistently creates groups that are most alike on the matching variable?

A)interval matching
B)precision matching
C)range matching
D)rank-ordered matching

Question 61

Multiple Groups An experimenter can use a ____ to determine the appropriate levels of an independent variable before conducting the actual experiment.

A)correlational study
B)field experiment
C)pilot study
D)placebo condition

Question 62

Multiple Groups A principal advantage of using more than two treatment conditions in an experiment is that this

A)better controls subject variables.
B)increases statistical power.
C)provides a more complete picture of how the independent variable affects behavior.
D)reduces variability in experimental data.

Question 63

Multiple Groups Lassen (1973) randomly assigned patients to sit 3, 6, or 9 feet away from a therapist and then had raters judge the patients' anxiety.Which design did she use?

A)experimental group-control group
B)multiple independent groups
C)multiple matched groups
D)two matched groups

Question 64

Multiple Groups Which of the following is a good "rule of thumb" for selecting an experimental design?

A)select a design based on the number of available subjects
B)add one more treatment condition than the last study used
C)select the simplest design that will adequately test your hypothesis
D)use a multiple independent groups design whenever possible

Question 65

Multiple Groups The main advantage of using block randomization instead of random assignment to place subjects in treatment groups is that

A)block randomization ensures an equal number of subjects in each condition.
B)block randomization does not use a random number table.
C)block randomization is simpler to perform than random assignment.
D)block randomization provides superior control of subject variables.

Question 66

Multiple Groups A researcher's decision to use more than two levels of the independent variable in an experiment mainly depends on

A)the dependent variable.
B)the estimated effect size.
C)the research hypothesis.
D)whether subjects will be run in more than one treatment condition.

Question 67

Multiple Groups Researchers often select extreme values of an independent variable because

A)extreme values increase the possibility of detecting a change across conditions.
B)extreme values produce results with greater external validity.
C)extreme values reduce the risk of confounding.
D)intermediate values provide minimal information about how the independent variable affects behavior.