Deck 6: Independent Groups Designs

Question 1

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable. At a nearby school, the researcher classified 5th-graders into one of three groups: intact parents (no divorce), divorced (single-parent families), and remarried parents. The researcher interviewed the 5th-graders and rated their sociability, and also asked them to complete a questionnaire that assessed their level of comfort of different social situations.
Suppose that the researcher finds that the 5^th graders in the divorce (single-parent)group are less sociable than are 5^th graders in the intact and remarried groups.The researcher concludes that divorce and living in a single-parent home causes children to be less sociable,and that remarriage causes improvements in sociability.Do you accept this researcher's conclusions? Why or why not?

Answer 1

This researcher incorrectly made a causal inference about the effects of divorce and remarriage based on a natural groups design.Natural groups designs provide correlational data regarding the relationship between an individual differences variable and a dependent variable;therefore,causal inferences cannot be made.These three groups may differ on a number of other variables (e.g. ,income,household stability,time since divorce)that may be related to children's sociability.These variables are potential alternative explanations for the observed group differences,rather than the three groups the researcher formed.

Question 2

One major purpose of conducting experiments is to decide whether a treatment or program effectively changes behavior.The second major purpose for doing experiments is to provide

A)an empirical test of hypotheses derived from theories.
B)simple and relatively quick ways of testing and revising hypotheses.
C)methods to obtain results that demonstrate that what we expect from our hypothesis will be confirmed.
D)definitive answers to theoretical questions.

Answer 2

definitive answers to theoretical questions.

Question 3

Describe how partial replications can be used to establish both experimental reliability and the external validity of research findings.

Answer 3

A partial replication involves changing some but not all of the original experiment.For instance,if an independent variable was shown to have an effect in an experiment testing only men,then a useful partial replication of this experiment would include the dimension of gender.In the partial replication both men and women would be tested while replicating all other conditions of the initial experiment.Experimental reliability can be demonstrated in partial replications when the same effect of the independent variable is obtained across the levels of the changed dimension (e.g. ,the independent variable has the same effect for men and women).Partial replications help to establish external validity by showing that a similar result occurs when slightly different experimental procedures are used,for example,with different participants and in a different setting.When similar results are obtained,we can say that the findings generalize across the participants and setting.

Question 4

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
The alternative explanation that participants in the very thin image condition had lower body satisfaction than other participants before they viewed the experimental images is ruled out because the researcher

A)replicated procedures used in previous experiments on exposure to thin images.
B)used introductory psychology students.
C)asked all participants to view 10 images for 1 minute each.
D)randomly assigned participants to conditions.

Question 5

Identify and briefly define the three primary types of control that are used in experiments.

Question 6

Explain how the procedures for conducting a matched groups design and a natural groups design differ from the random groups design.

Question 7

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
The scores on the questionnaire about body satisfaction represent the

A)level of significance.
B)independent variable.
C)dependent variable.
D)control variable.

Question 8

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
The use of very thin images and neutral images in this study represents

A)a partial replication of previous findings for the effects of viewing body images.
B)a block randomization procedure.
C)a confidence interval for the population means.
D)none of these

Question 9

Describe briefly how confidence intervals can be used to determine if the means for the two conditions of an experiment differ.

Question 10

Clearly and concisely describe how a researcher could minimize the likelihood of selective subject loss in an experiment--be sure to include in your answer any risks that the researcher would be taking in trying to prevent the selective loss.

Question 11

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
The alternative explanation that extraneous variables produced the different body satisfaction scores is ruled out because the researcher

A)replicated procedures used in previous experiments on exposure to thin images.
B)used introductory psychology students.
C)asked all participants to view 10 images for 1 minute each.
D)randomly assigned participants to conditions.

Question 12

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable. At a nearby school, the researcher classified 5th-graders into one of three groups: intact parents (no divorce), divorced (single-parent families), and remarried parents. The researcher interviewed the 5th-graders and rated their sociability, and also asked them to complete a questionnaire that assessed their level of comfort of different social situations.
What type of experimental design did this researcher use?

Question 13

Briefly outline the steps involved in order to make an inference about the effect of an independent variable using null hypothesis significance testing;be sure to indicate the conditions in which an independent variable is judged to be nonsignificant and when it is statistically significant.

Question 14

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable. At a nearby school, the researcher classified 5th-graders into one of three groups: intact parents (no divorce), divorced (single-parent families), and remarried parents. The researcher interviewed the 5th-graders and rated their sociability, and also asked them to complete a questionnaire that assessed their level of comfort of different social situations.
Describe the dependent variable(s)in this study.

Question 15

A researcher was interested in whether divorce and remarriage influence the extent to which children are sociable. At a nearby school, the researcher classified 5th-graders into one of three groups: intact parents (no divorce), divorced (single-parent families), and remarried parents. The researcher interviewed the 5th-graders and rated their sociability, and also asked them to complete a questionnaire that assessed their level of comfort of different social situations.
Describe the independent variable in this study.

Question 16

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
Assume the average variability of participants' body satisfaction scores is 1.0.Based on this we can state that the effect of viewing very thin images compared to athletic images is

A)small,d = .25.
B)medium,d = .75.
C)large,d = 1.0.
D)extra large,d = 2.0.

Question 17

The factors that researchers control or manipulate in order to determine their effect on behavior are called the

A)intervention variables.
B)independent variables.
C)dependent variables.
D)confounding variables.

Question 18

When researchers use the multimethod approach they can reach comparable conclusions about a research question after using different methods to study it.Our confidence in these conclusions increases and the conclusions are said to have

A)concurrent validity.
B)convergent validity.
C)multiple validity.
D)crossing validity.

Question 19

Figure:
A researcher tested whether exposure to images of very thin fashion models causes young women to be dissatisfied with their own body,compared to exposure to athletic body images or neutral (non-body)images.She randomly assigned 60 women from an introductory psychology course to one of three exposure conditions: very thin female body images,athletic female images,or neutral images.Each condition had 10 images,projected individually on a large screen.The young women participated in small groups.Each image was displayed for 1 minute,for a total of 10 minutes of exposure.After viewing each image,participants wrote for 30 seconds a description of the image (the participants were led to believe their memory was being tested).After viewing the images,the women completed a questionnaire about satisfaction with their body.Negative scores indicate body dissatisfaction and positive scores indicate satisfaction with their body.The mean scores for each condition were as follows:
The three image conditions represent the

A)natural groups variable.
B)independent variable.
C)dependent variable.
D)control variable.

Question 20

Identify the two major reasons why psychologists conduct experiments.

Question 21

Two control techniques that allow researchers to rule out alternative explanations for an outcome are balancing and

A)establishing a covariation.
B)establishing a time-order relationship.
C)using a matched groups design.
D)holding conditions constant.

Question 22

In order to conduct an experiment more efficiently a researcher tests groups of participants in several small groups.The sizes of the groups differ because of differences in participants' availability at different times.The different sizes of the groups represent a potential

A)intact group problem.
B)selective subject loss problem.
C)extraneous variable problem.
D)experimenter effect.

Question 23

In a study that investigates the effects of two different doses of a drug on memory performance,the drug doses represent the ____ variable and memory performance represents the ____ variable.

A)correlational,confounding
B)experimental,control
C)dependent,independent
D)independent,dependent

Question 24

When participants begin an experiment but fail to complete it,the internal validity of the experiment can be threatened.Which of the following types of subject loss poses the most serious threat to internal validity?

A)the loss is selective in that some characteristic of the participant that is related to the outcome of the study is responsible.
B)the loss occurs because of an error by the experimenter.
C)the loss leads to different numbers of participants in the groups in the experiment.
D)the loss occurs because of equipment failure.

Question 25

Random assignment to conditions works to balance participants' individual differences across conditions of the experiment by

A)matching individuals on key variables.
B)generating groups of participants that are equivalent,on average.
C)forming groups based on an individual differences variable the researcher selects.
D)asking individuals to participate in each condition of the experiment.

Question 26

Which of the following arises when the independent variable of interest and a potential independent variable are allowed to covary?

A)contamination effect
B)decrease in external validity
C)confounding
D)illusory correlation

Question 27

The three steps of data analysis are

A)check the data,summarize the data,and confirm what the data reveal.
B)find any outliers,compute confidence intervals,and do null hypothesis significance testing.
C)find Type I and Type II errors,compute means,and compute inferential statistics.
D)calculate the standard deviation,find the effect size,and do null hypothesis significance testing.

Question 28

Subject loss (attrition)poses a problem for a random groups design because

A)extraneous variables are more likely to affect subjects who drop out.
B)participants may change their natural group designation.
C)participants may no longer be blind to the manipulation.
D)group equivalence established at the beginning of the experiment may be lost.

Question 29

If participants know they have been given alcohol,they may expect certain effects such as giddiness or relaxation.The general term for such cues that guide participants' behavior in a study is

A)double-blind effects.
B)self-preoccupation characteristics.
C)demand characteristics.
D)expectation effects.

Question 30

Placebo control groups and double-blind procedures are typically used to control for

A)individual differences variables.
B)the influence of extraneous variables.
C)the possibility of selective subject loss.
D)demand characteristics and experimenter effects.

Question 31

An instructor randomly assigns two sections of his course to an experimental condition (new teaching method)or control condition (regular teaching method).Students in the 9:30 section receive the experimental treatment and students in the 1:30 section participate in the control condition.At the end of the semester the instructor's tests reveal that students in the 9:30 section had higher test scores than students in the 1:30 section,based on a test of statistical significance.Based on this summary,we can state that

A)the results are uninterpretable because of intact groups.
B)the findings have external validity across two times of day.
C)the experiment has internal validity.
D)all of these

Question 32

A researcher randomly assigns one classroom to a new teaching method and a second classroom to the control condition (the regular teaching method).This researcher faces the potential problem of confounding due to

A)experimenter effects.
B)selective subject loss.
C)extraneous variables.
D)intact groups.

Question 33

The characteristics of the participants tested in an experiment are called individual differences variables.Individual differences among participants are controlled in an experiment by

A)eliminating the individual differences from the experiment.
B)balancing the individual differences across the conditions of the experiment.
C)ignoring the individual differences because they cannot confound the experiment.
D)holding the individual differences constant in the experiment.

Question 34

The goal of a random groups design experiment is to establish the independent variable as the cause of a differences in the dependent variable.The logic of accomplishing this involves

A)beginning with noncomparable groups,treating them the same,and ending with noncomparable groups.
B)beginning with noncomparable groups,treating them differently,and ending with comparable groups.
C)beginning with comparable groups,treating them the same,and ending with noncomparable groups.
D)beginning with comparable groups,treating them differently,and ending with noncomparable groups.

Question 35

The most common solution to the problem of forming comparable groups in the random groups design is

A)random-digit dialing.
B)random selection.
C)random assignment.
D)matching participants on the dependent variable task.

Question 36

In addition to creating groups of equal size,an advantage of block randomization is that it

A)decreases the number of participants needed in each condition.
B)balances potential confoundings that occur during the time in which an experiment is run.
C)improves that likelihood that there will be individual differences among participants in the conditions of the experiment.
D)averages the effect of the dependent variable across the conditions of the experiment.

Question 37

A researcher has manipulated only one independent variable at two levels,has held constant as many other variables as possible and has balanced individual differences by using random assignment.The researcher is likely to be able to claim that the independent variable caused the observed changes in the dependent variable because the experiment is

A)internally valid.
B)externally valid.
C)a meta-analysis.
D)reliable.

Question 38

A researcher examined participants' memory following emotionally shocking events by manipulating whether participants viewed a violent or a nonviolent version of a video.The video in the two conditions was identical except for two seconds in which the violence variable was manipulated.That the video was identical except for the manipulation represents the control technique of

A)balancing the individual differences across the groups of the experiment.
B)confounding the independent variable.
C)a time-order relationship between the independent and dependent variables.
D)holding conditions constant in the experiment.

Question 39

When the three requirements for causal inference are met,an experiment is said to be

A)confounded.
B)an independent groups design.
C)internally valid.
D)held constant.

Question 40

Which of the following is the best way to determine whether the differences in means obtained in an experiment are reliable?

A)perform an inferential statistics test (null hypothesis significance testing).
B)use confidence intervals to compare the means.
C)replicate the experiment.
D)find the difference between two sample means.

Question 41

The problem of Type I and Type II errors occurs because

A)researchers rarely conduct internally valid experiments.
B)decision making based on inferential statistics depends on probabilities.
C)the null hypothesis is difficult to define.
D)all of these

Question 42

We can be confident that the population means differ for two conditions of an experiment when the confidence intervals for the two sample means

A)overlap.
B)do not overlap.
C)are of different size.
D)have different standard deviations.

Question 43

After checking the data for errors and outliers,the next step in analyzing the data from a research study is to use

A)descriptive statistics.
B)meta-analysis.
C)confidence intervals.
D)inferential statistics and null hypothesis significance testing.

Question 44

________ refers to the researcher's ability to make causal inferences regarding an experimental outcome and _________ refers to the researcher's ability to generalize the findings beyond the scope of the specific experiment.

A)Internal validity;external validity
B)External validity;internal validity
C)Reliability;validity
D)Replication;confounding

Question 45

Two statistical methods that researchers use to determine whether an independent variable has a reliable effect on a dependent variable are

A)error variation and effect size.
B)statistical significance and odds variation.
C)null hypothesis significance testing and confidence intervals.
D)Cohen's d and alpha.

Question 46

When the findings of experiments testing the effectiveness and safety of drugs on animals are confirmed in clinical trials with people,the original findings of the animal research are shown to have

A)external validity.
B)internal validity.
C)statistical significance.
D)sensitivity.

Question 47

A statistically significant outcome is an outcome that

A)leads to a modification in a psychological theory.
B)leads us to reject the null hypothesis.
C)assures that practical applications of the outcome will be successful.
D)assures the internal validity of the experiment.

Question 48

A researcher observes that the mean difference between two conditions is 2.0 and the average variability in participants' scores is 4.0.The effect size,Cohen's d,for this experiment is _______.

A)8.0
B)4.0
C)2.0
D)0.5

Question 49

A researcher computes a .95 confidence interval for an experimental group to be 2.0 - 8.0,and computes a .95 confidence interval for a control group to be 0.0 - 4.0.Based on these confidence intervals,the researcher can state that

A)the results for the effect of the independent variable on the dependent variable are inconclusive.
B)the independent variable definitely influenced participants' scores on the dependent variable because the upper limit of the confidence interval is twice that of the control group.
C)the independent variable definitely did not affect participants' scores because the lower limit of the confidence interval for the control group is zero.
D)the population value for the experimental group is .95.

Question 50

The statistical tool that is used to analyze the results of several independent experiments is called

A)F-test analysis.
B)meta-analysis.
C)omni-analysis.
D)Cohen's d analysis.

Question 51

Which of the following is a measure of the strength of the relationship between the independent and dependent variables that is independent of sample size?

A)F-test
B)error variation
C)effect size
D)residual variation

Question 52

The researcher should

A)reject the null hypothesis of no difference between the experimental and control groups because the probability is so small;thus,the independent variable had a reliable effect on the dependent variable.
B)accept the null hypothesis of no difference between the experimental and control groups because the probability is so small;thus,the independent variable had no effect.
C)neither accept nor reject the null hypothesis of no difference because the probability value of .025 is significantly different than .05.
D)reduce the alpha level of significance to .025 to form a definite conclusion.

Question 53

When the results on an experiment are likely to be replicated if the procedures are repeated,we are more confident the findings are not due to chance factors.When this occurs we state our findings are

A)internally valid.
B)sensitive.
C)reliable.
D)extraneous.

Question 54

When we conclude that an experiment does not provide sufficient evidence to reject the null hypothesis when,in fact,an independent variable does produce an effect,the inferential statistics problem is called a

A)no-confidence interval.
B)probability error.
C)Type I error.
D)Type II error.

Question 55

A Type I error occurs when the null hypothesis is really true and we claim

A)the independent variable did not have an effect on behavior.
B)the inferential test was not statistically significant.
C)that the results are not significant.
D)the independent variable did have an effect on behavior.

Question 56

Which of the following is not an advantage of using measures of effect size?

A)Measures of effect size provide information about the strength of the relationship between an independent variable and a dependent variable.
B)Measures of effect size can be used to make quantitative comparisons of the different outcomes found in a series of experiments involving the same independent variable.
C)Measures of effect size can provide an estimate of the overall effect size for an independent variable by averaging effect sizes across a series of experiments.
D)Measures of effect size provide the best information about whether the effect of the independent variable is statistically significant.

Question 57

.Which of the following best describes the outcome of this clinical trial?

A)The drug did not have a reliable effect but it would still likely lead to a large weight loss for people who use it.
B)The drug did not have a reliable effect and it would lead to a small weight loss for people who use it.
C)The drug had a reliable effect that will likely lead to a large weight loss for people who use it.
D)The drug had a reliable effect that will likely lead to a small weight loss for people who use it.

Question 58

Our ability to draw appropriate conclusions based on the results of an experiment depends most of all on the

A)internal validity of the experiment.
B)external validity of the findings.
C)amount of variation in the experiment.
D)statistical significance of the findings.

Question 59

A statistically significant outcome is an outcome that

A)has a large likelihood of occurring if the null hypothesis is true.
B)has a small likelihood of occurring if the null hypothesis is true.
C)occurs in 5 out of every 100 experiments (p = .05).
D)has neither Type I nor Type II errors.

Question 60

The nonsystematic variation due to differences among subjects within each group is called

A)spurious variation.
B)error variation.
C)meta-variation.
D)nonsignficant variation.

Question 61

Which of the following conditions would lead you to recommend against the use of a matched groups design and in favor of a random groups design?

A)a large number of participants from a homogeneous population is available
B)a small number of participants from a heterogeneous population is available
C)a separate group is required for each level of the independent variable of interest
D)a reliable and valid matching task is available

Question 62

A cognitive psychologist wants to do an experiment testing the memory of elderly people.She has the following constraints: only 12 people available as possible participants and the independent variable she is manipulating requires the use of separate groups for each condition.The psychologist has a reliable and valid pretest she plans to use.Which design is this psychologist likely to use?

A)matched groups design
B)natural groups design
C)random groups design
D)placebo control design

Question 63

When conducting an experiment using the matched groups design,the preferred pretest task (matching task)is

A)completely different from the dependent variable.
B)an inexpensive task that participants could complete quickly.
C)the same task that will be used as the dependent variable.
D)a task with limited reliability and validity.

Question 64

A researcher has read a research report indicating that a certain medication has been found to be effective when tested on men.The researcher plans to do an experiment testing the effectiveness of the same medication but in his experiment both men and women will be tested.The researcher is planning to do a

A)replication of the experiment to test the internal validity of the original experiment.
B)partial replication of the experiment to test the external validity of the finding from the original experiment.
C)replication of the experiment to test the sensitivity of the original experiment.
D)partial replication of the experiment to test the statistical power of the original experiment.

Question 65

The natural groups design represents an illustration of the general research approach that is called

A)descriptive research.
B)correlational research.
C)experimental research.
D)observational research.

Question 66

Researchers found a relationship between insults and aggressive behavior for 5-year olds.If they want to test the external validity of the conceptual relationship between insults and aggressive behavior for a sample of 35-year olds,they should

A)use age-appropriate insults and measures of aggression for the 35-year olds.
B)use the same measure of aggression as was used with the 5-year olds.
C)test the findings in the real world rather than in a laboratory setting.
D)use the same insults as was used with the 5-year olds.

Question 67

Which of the following is the most critical problem in drawing causal inferences based on the natural groups design?

A)establishing covariation.
B)correlating participants' characteristics and their performance.
C)specifying the direction of the potential causal relationship.
D)eliminating plausible alternative causes for the obtained relationship.

Question 68

To differentiate experiments involving individual differences (subject)variables and those involving manipulated independent variables,those experiments involving individual differences (subject)variables are called

A)selected groups designs.
B)matched groups designs.
C)natural groups designs.
D)randomized designs.

Question 69

In what situation is it argued that external validity is irrelevant?

A)when psychologists seek to describe real-world settings based on laboratory research
B)when research is conducted with college student samples.
C)when the purpose of the experiment is to test a specific hypothesis derived from a theory.
D)when the goal of an experiment is to set up the most typical case found in nature.