Deck 11: Designing, Conducting, Analyzing, and Interpreting Experiments With More Than Two Groups

Question 1

Why is a probability value of .000 slightly misleading?

Answer 1

The tails of distributions are asymptotic, which means that they extend into infinity and never touch the baseline. You can get probability values that are very close to zero as you move farther into the tail, but never actually zero. A probability value of .000 suggests, in essence, that there is a 0% chance of making a Type I error, which is incorrect.

Question 2

What kind of statistical analysis was conducted?

Answer 2

The statistical analysis is a one-way ANOVA for correlated groups.

Question 3

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).

This study is an independent groups design. How do you know?

Answer 3

This is an independent groups design because participants were randomly assigned to condition.

Question 4

Write an APA-format conclusion for these results.

Question 5

What is the dependent variable in this study?

Question 6

What is the dependent variable in this study?

Question 7

What is the independent variable in this study?

Question 8

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).

How could you change this experiment to be a matched sets design?

Question 9

Why does "DF Clothing" = 2?

Question 10

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).

How could you change this experiment to be a repeated measures design?

Question 11

What is the scale of measurement for the dependent variable?

Question 12

Is this a two-group design or a multiple-group design? How do you know?

Question 13

Write an APA-format conclusion for these results.

Question 14

In the following study, participants were randomly assigned to receive humanistic therapy, psychodynamic therapy, or behavioral therapy for their depression. Six months after therapy ended, participants' levels of depression were rated on a Likert scale from 1 (not at all depressed) to 15 (extremely depressed).

Is this a two-group design or a multiple-group design? How do you know?

Question 15

Did the independent variable have a significant effect on the dependent variable? How do you know?

Question 16

What kind of statistical analysis was conducted?

Question 17

This is a correlated groups design. How do you know?

Question 18

Is this a true experiment or an ex post facto study? How do you know?

Question 19

What is the independent variable in this study?

Question 20

Did the independent variable have a significant effect on the dependent variable? How do you know?

Question 21

Which of the following is the FIRST question researchers should ask themselves when considering any experimental design?

A) How many groups (levels) will my independent variable have?
B) What type of participant groups do I have (independent or correlated)?
C) How many independent variables will my experiment have?
D) How many confounds should I include?

Question 22

A multiple-group experiment often consists of

A) an experimental group and a control group.
B) an experimental group.
C) all control groups.
D) two or more experimental groups and a control group.

Question 23

Examine the results in Table 1 on p. 384 of the article. In APA-format, explain (in words) the results for Muscularity (M).

Question 24

Examine the results in Table 1 on p. 384 of the article. Do these results come from an independent-groups design or a correlated-groups design? How do you know?

Question 25

Miguel conducts a study in which he compares the effectiveness of behavioral therapy, cognitive therapy, humanistic therapy, and psychodynamic therapy to treat phobias. In this study, the independent variable is _________ and it has ____ level(s).

A) type of therapy; one
B) type of therapy; four
C) effectiveness of therapy; one
D) effectiveness of therapy; four

Question 26

According to your text, "You find a research idea when you identify a gap in the current knowledge base…" . What was the gap in the knowledge base, according to the authors?

Question 27

Cathy examined the effect of different teaching methods on students' exam performance. She randomly assigned college students to listen to one of three lectures and then tested them over the material. As hypothesized, she found that students taught by Method 1 earned significantly higher exam grades than students taught by Method 2 or Method 3. Which of the following is the best conclusion to draw from these results?

A) Because Cathy has not done an experiment, she should not draw any cause-and-effect conclusions.
B) Cathy has proven that Method 1 is superior to Method 2 and Method 3.
C) Cathy's results supported the hypothesis.
D) Cathy's study has high external validity.

Question 28

A multiple-group design compares _________ level(s) of the independent variable.

A) one
B) two
C) one or two
D) three or more

Question 29

The belief that explanations of phenomena should remain simple until the simple explanations are no longer valid is known as the

A) error variability.
B) asymptotic principle.
C) principle of parsimony.
D) placebo principle.

Question 30

Groups of participants that are formed by random assignment are known as _________ groups.

A) correlated
B) independent
C) matched pairs
D) natural pairs

Question 31

Groups of participants that are related in some way are known as _________ groups.

A) random
B) independent
C) correlated
D) confounded

Question 32

Examine the results in Table 1 on p. 384 of the article. In APA-format, explain (in words) the results for Muscularity (F).

Question 33

Describe in your own words self-discrepancy theory.

Question 34

What makes "self-discrepancy theory" a theory and not, for instance, a hypothesis?

Question 35

Participants who receive the IV are referred to as the _________ group.

A) control
B) treatment
C) confound
D) random

Question 36

Examine the Measures section on p. 382 of the article. What is the scale of measurement for the muscularity variable? What is the scale of measurement for the hair color variable?

Question 37

Examine the results in Table 1 on p. 384 of the article. In APA-format, explain (in words) the results for Weight (M).

Question 38

Suppose you know you would like to conduct a one-IV experiment. What is the second question that you need to answer?

A) How many levels of the IV will I use?
B) Will I conduct an experiment or a correlational study?
C) Will I conduct a confounded experiment or a true experiment?
D) All of the above.

Question 39

Examine the results in Table 1 on p. 384 of the article. In APA-format, explain (in words) the results for Weight (F).

Question 40

Examine the results in Table 1 on p. 384 of the article. Why did the authors analyze the data using an ANOVA instead of a t test?

Question 41

When you use _________, each participant must take place in all the various treatment conditions.

A) matched sets
B) natural sets
C) repeated measures
D) random assignment

Question 42

Lisa is conducting a study using sets of siblings. She assigns each sibling from a family into a different group. Lisa is using _____ sets.

A) repeated
B) matched
C) natural
D) independent

Question 43

Which of the following is a disadvantage of using natural sets in a multiple-group experiment?

A) There is more error variability in natural sets than in random assignment.
B) It is difficult to find enough participants.
C) A natural sets design does not equate the groups as well as random assignment does.
D) All of the above.

Question 44

In what way is a two-group design different from a multiple-group design?

A) You add another independent variable.
B) You add another dependent variable.
C) You add another level to an independent variable.
D) You add another level to a dependent variable.

Question 45

If each participant in an experiment has an equal chance of being in any of the groups, then the researcher has used __________ assignment.

A) correlated
B) random
C) nonrandom
D) ex post facto

Question 46

___________ designs have decreased error variability compared to __________ designs.

A) Independent groups; correlated groups
B) Correlated groups; independent groups
C) Natural sets; correlated groups
D) Repeated measures; matched sets

Question 47

What happens when we match participants on a variable that is unrelated to the dependent variable?

A) We increase our chances of finding a significant effect.
B) We decrease our chances of finding a significant effect.
C) We increase the generalizability of our experiment.
D) We decrease our chances of having experimenter bias in the study.

Question 48

Which of the following is NOT a way to create correlated groups?

A) Repeated measures
B) Matched sets
C) Natural sets
D) Random assignment

Question 49

Which of the following is NOT a control procedure?

A) Random assignment
B) Matching
C) Natural sets
D) Convenience sampling

Question 50

Researchers form ________ sets by measuring participants on some variable that will affect their performance on the DV.

A) random
B) independent
C) matched
D) natural

Question 51

Larry conducts an experiment with three groups: (1) writing about traumatic events, (2) writing about happy events, and (3) writing about neutral events. Larry then measures the number of visits each participant makes to the health center over the next six months. Larry gives the participants a pretest regarding their health visits prior to the study so that he can create sets of participants who are equivalent on that variable. Participants are randomly assigned to condition from each set. Larry has used _________ sets.

A) natural
B) independent
C) repeated measures
D) matched

Question 52

Latitia conducted an experiment in which all the men watched an aggressive television program, and all the women watched a non-aggressive television program. Her results showed that people who watched the aggressive program were later more aggressive than people who watched the non-aggressive program. She concludes that aggressive television programming is detrimental. What is the biggest problem in Latitia's experiment?

A) She has not used random selection procedures.
B) She has confounded gender and type of television program.
C) She should have used a correlated-groups design instead of an independent-groups design.
D) None of the above; there are no problems in Latitia's experiment.

Question 53

If a researcher has used random assignment, then

A) the groups should be equalized on potential extraneous variables.
B) participants are matched on characteristics thought to be important for the dependent variable.
C) participants experience the dependent variable two or more times.
D) everyone in the population has an equal chance of being included in the experiment.

Question 54

Darryl conducts a study in which participants rate their liking for their professor on the first day of class, at midterm, and on the last day of class. Darryl has used which research design?

A) Matched sets
B) Natural sets
C) Independent groups
D) Repeated measures

Question 55

Researchers often choose a correlated-groups design over an independent-groups design when

A) their sample size is small.
B) they expect small differences owing to their IV.
C) they want to reduce error variance.
D) All of the above.

Question 56

__________ error variability will __________ your likelihood of finding a significant effect.

A) Increasing; not affect
B) Decreasing; decrease
C) Decreasing; increase
D) Decreasing; not affect.

Question 57

Which of the following is a disadvantage of using repeated measures in a multiple-group experiment?

A) Participants might get bored.
B) It is difficult to find enough participants.
C) A repeated measures design does not equate the groups as well as random assignment does.
D) All of the above.

Question 58

The general equation for any statistical test is

A) Error variability/within-groups variability
B) Error variability/between-groups variability
C) Between-groups variability/error variability
D) Within-groups variability/between-groups variability

Question 59

Suppose you were interested in conducting a repeated measures experiment with 15 levels. Which of the following might be your greatest concern?

A) Will participants become bored or fatigued over time?
B) Will I be able to secure enough participants for that many groups?
C) Will I be able to find significant effects given that I am using so few groups?
D) Will the groups be equivalent before the study begins?

Question 60

An experiment in which an extraneous variable varies systematically with the IV is a(n) ________ experiment.

A) ex post facto
B) correlated-groups
C) confounded
D) true

Question 61

_________ groups designs have decreased error variability compared to _____________ groups designs.

A) Independent; correlated
B) Correlated; matched sets
C) Correlated; independent
D) Matched sets; correlated

Question 62

__________ degrees of freedom makes it __________ to achieve statistical significance.

A) Fewer; easier
B) Fewer; harder
C) Fewer; impossible
D) Fewer; certain

Question 63

What kind of statistical analysis would you conduct if you used multiple groups and correlated groups of participants?

A) repeated-measures t-test
B) repeated-measures ANOVA
C) completely randomized ANOVA
D) independent samples t test

Question 64

A statistical test used to analyze data from an experiment with one independent variable that has three or more groups is known as a

A) two-factor ANOVA.
B) t-test.
C) one-way ANOVA.
D) z-test.

Question 65

Daisy conducts a study in which a sample of rats receives a high dose of alcohol on one day, a low dose of alcohol on one day, and no alcohol on one day. Each day, she measures the time it takes them to learn a new maze. What statistical technique should Daisy use to analyze her data?

A) completely randomized ANOVA
B) repeated-measures t test
C) repeated-measures ANOVA
D) repeated-measures three-factor ANOVA

Question 66

Research conducted with a measured rather than manipulated independent variable is referred to as __________ research.

A) ex post facto
B) repeated measures
C) correlated groups
D) independent groups

Question 67

An experimental effect caused by expectation or suggestion rather than the IV is known as

A) a parsimonious effect.
B) error variability.
C) randomization.
D) a placebo effect.

Question 68

A(n) ___________ groups design has fewer degrees of freedom compared to a(n) ___________ groups design.

A) independent; correlated
B) correlated; independent
C) natural sets; matched sets
D) correlated; matched sets

Question 69

Which of the following is a practical consideration in a multiple-independent-groups design?

A) You will need a large number of participants to fill the multiple groups.
B) You will need a large number of participants to conduct proper matching of a variable of interest.
C) You will need to guard against participants becoming bored or fatigued over many administrations of the dependent variable.
D) All of the above.

Question 70

Ex post facto research uses a __________ independent variable.

A) true
B) manipulated
C) measured
D) placebo

Question 71

What is one limitation of using natural sets in a multiple-group design?

A) The probability of finding a significant result is lower compared to when you use independent groups.
B) There is not as much control in the experiment compared to an independent-groups design.
C) Natural sets that are large enough may be difficult to obtain.
D) There is an increased risk of experimenter bias with natural sets.

Question 72

Rich has conducted a study in which he compares the reading skills of 6-year-olds, 7-year-old, and 8-year-olds. What kind of statistical test should Rich use?

A) one-way ANOVA
B) t-test
C) three-way ANOVA
D) Pearson product-moment correlation coefficient

Question 73

When you assign your participants to multiple groups randomly, you analyze your data using a _____________ ANOVA.

A) repeated-measures
B) correlated-groups
C) completely randomized
D) within-subjects

Question 74

Melinda conducts a study in which some participants receive an antidepressant, others receive a sugar pill that they think is an antidepressant, and the rest receive nothing at all. She finds that both the antidepressant group and the sugar pill group report being less depressed than the control group. Melinda has conducted a(n) _____________ study and the results for the sugar pill group are likely due to a ____________ effect.

A) repeated measures; placebo
B) repeated measures; sugar
C) independent groups; placebo
D) independent groups; sugar

Question 75

Nina obtains a sample of people who are classified as low, medium, and high in generalized anxiety. She then measures their persistence on a difficult laboratory task. Nina's research would best be classified as __________ research.

A) repeated measures
B) correlated groups
C) ex post facto
D) true experiment

Question 76

What kind of definitions do researchers use when planning their experiments?

A) dictionary definitions
B) operational definitions
C) ANOVA definitions
D) summarized definitions

Question 77

Courtney conducts a study in which she randomly assigns some rats to receive a high dose of alcohol, other rats to receive a low dose of alcohol, and a final group receives no alcohol. She measures the time it takes them to learn a new maze. Courtney's study represents a(n) __________ and her statistical technique for analyzing the data should be a ___________.

A) ex post facto design; repeated-measures ANOVA
B) ex post facto design; completely randomized ANOVA
C) true experiment; completely randomized ANOVA
D) true experiment; repeated-measures ANOVA

Question 78

When error variability __________, it is ________ to reject the null hypothesis.

A) increases; easier
B) increases; not possible
C) decreases; easier
D) decreases; not possible

Question 79

What is one way to operationally define "casual clothing" in an experiment in which you manipulate the type of clothing customers where to a store?

A) clothing that is laid-back and not formal
B) clothing that is not dressy but also not sloppy
C) clothing that college-aged students would typically wear
D) khakis and polo shirts

Question 80

On average, when error variability _________, the statistical value _________.

A) increases; increases
B) decreases; decreases
C) increases; remains the same
D) decreases; increases