Research Methods Test 3

Factorial Design

-A research design that includes two or more factors (IVs) *a two-factor design has two IVs *a single-factor design has one IV *2 x 3 x 2 design is a three-factor design with a total of 12 conditions

Between-Subjects Design

-Also known as an independent-measures experimental design -Requires a separate, independent group of individuals for each treatment condition -The data for a between-subjects design contain only one score for each participant

Counterbalancing

-Changing the order in which treatment conditions are applied from one participant to another -Matches treatment conditions with respect to time -Goal is to use every possible order of treatments with an equal number of subjects participating in each sequence -Purpose is to eliminate time-related confounding

Cross-Sectional Longitudinal Designs

-Compares the results obtained from separate samples (like a cross-sectional design) that were obtained at different times -Examines the development of phenomena other than individual aging

Internal Validity in Between-Subjects Designs

-Confounding from individual differences (assignment bias) -Confounding from environmental variables

Nonequivalent Group Design

-Different groups of participants are formed under circumstances that do not permit the researcher to control the assignment of individuals to groups *the researcher cannot use random assignment to create groups of participants

Advantages of Between-Subjects Designs

-Each individual score is independent from the other scores -Can we used for a wide variety of research questions (always an option even when not the best choice)

Disadvantages of Within-Subjects Design

-Each participant usually goes through a series of treatment conditions, often with each treatment administered at a different time *may lead to time-related factors which influence the subjects' scores -Participant attrition: Some of the subjects who start the study will drop out before the study is completed

A Within-Subjects Design

-Has no individual differences between groups; there is only one group of participants -The group in one treatment is exactly the same as the group in every other treatment -Result is no individual differences between groups to confound the study *each subject appears in every treatment condition *each subject serves as his own control

What are time-related threats?

-History -Maturation -Instrumentation -Regression toward the mean -Order effects (practice, fatigue, and carry-over effects)

Longitudinal Developmental Research Design

-Involves measuring a variable in the same group of individuals over a period of time *an example of a within-subjects nonexperimental design -A set of observations is followed by a period of development or aging, then another set of observations *differences between observations define the effects of development

Interaction Between Factors

-One factor has a direct influence on the effect of a second factor *ex: one drug modifying (exaggerating or minimizing) the effects of another drug -Independent factors have no interaction

Time-Series Designs

-Possible to see the trend in the data that existed before the treatment was administered and that continues after the treatment

Advantages of Within-Subjects Design

-Requires relatively few participants -Eliminates problems based on individual differences -Reduces variance (increases the chances of detecting a treatment effect)

The Structure of a Within-Subjects Design

-Same group of individuals participates and is measured in all treatments *not necessarily in the same order

Single-Factor Two-Group Design

-Simplest version of a between-subjects experimental design -Compares only two groups of participants -Researcher manipulates one independent variable with only two levels *used to compare treatments or to evaluate the effect of one treatment by comparing a treatment group and a control group

Nonexperimental Developmental Research Designs

-The cross-sectional developmental research design uses different groups of individuals *each group represents a different age -The different groups are measured at one point in time and then compared -This design is an example of a between-subjects nonexperimental design

Nonexperimental Designs with Nonequivalent Groups

-The differential research design: A research study that compares preexisting groups *goal is to establish differences between the preexisting groups *also called an ex post facto design- looks at differences after the fact -The posttest only nonequivalent control group design uses preexisting groups *one group serves in the treatment condition *a second group of similar but nonequivalent participants is used for the control condition *there is no random assignment to groups

The Structure of Nonexperimental and Quasi-Eperimental Research Strategies

-The distinction between the two types of designs is the degree to which the research strategy limits confounding variables and controls threats to internal validity *a nonexperimental design makes little or no attempt to minimize threats *a quasi-experimental design makes some attempt to minimize threats to internal validity- is almost, but not quite, a true experiment

Two-Factor Design

-The levels of one factor determine the columns and the levels of the second factor determine the rows -Can be represented by a matrix *each cell corresponds to a separate treatment condition -Data provide three separate and distinct sets of information *describes how the two factors independently and jointly affect behavior

Main Effects

-The main effect is the mean differences among the levels of one factor *a two-factor study has two main effects, one for each factor

Dealing with Time-Related Threats and Order Effects

-The possibility of a time-related threat is directly related to the length of time required to complete the study -Shortening the time between treatments increases the likelihood that order effects will influence results -Increasing the time between treatments increases the risk of time-related threats to internal validity -Switching to a between-subjects design is a better choice for research conditions that are prone to order effects

Disadvantages of Between-Subjects Designs

-They require a relatively large number of participants -Each score is obtained from a unique individual (individual differences)

Threats to Internal Validity to Within-Subjects Experiments

-Two major sources of potential confounding: 1. Confounding from environmental variables *characteristics of the environment may change from one treatment condition to another 2. Confounding from time-related variables *Between the first measurement and the final measurement, participants may be influenced by factors other than the treatment being investigated

Within Subjects Designs

-Uses a single group of participants and tests or observes each individual in all of the different treatments being compared -Same group of individuals participates in every level of the IV -Often called a repeated-measures design -Study repeats measurements of the same individuals under different conditions

A prison psychologist measures depression for a group of prisoners each day for one week before and for one week after the psychologist begins a series of group therapy sessions. This is an example of a(n) ____ design. A. time series B. interrupted time series C. equivalent time samples D. one-group pretest-posttest design

A

A researcher is examining motor skill development by observing children at 18 months, 24 months, and 30 months. If the researcher uses a longitudinal design and obtains 20 scores for each age, then how many children participated in the entire study? A. 20 B. 40 C. 60 D. Cannot determine without more information

A

How many participants would be needed for a two-factor experiment with two levels of Factor A and three levels of Factor B if both factors are within subjects and there are five scores in each treatment condition? A. 5 B. 10 C. 15 D. 30

A

In a factorial experiment, the number of factors is the number of ____ A. independent B. dependent C. extraneous D. confounding

A

The internal validity of the pre-post designs is threatened by A. threats related to time B. threats related to difference between groups C. differential effects D. the other three choices are all threats to pre-post designs

A

When an outside event occurs during a within-subject study and influences some of the treatment conditions but not others, the results are confounded by ____ A. history effects B. instrumentation C. maturation D. regression toward the mean

A

Which of the following accurately describes nonequivalent group design? A. The researcher cannot control which people go into each group and cannot ensure that the groups are equivalent B. The two groups have completely different characteristics C. The researcher randomly assigns people to groups, so there is no guarantee that the groups are equal D. The number of participants is different from one group to another

A

Which of the following is the correct description for a research study comparing problem-solving scores obtained under three different levels of temperature? A. single-factor design B. two-factor design C. three-factor design D. factorial design

A

A quasi-experimental design A. makes no attempt to minimize threats to validity B. makes some attempts to minimize threats to validity C. controls extraneous variables, similar to an experiment D. manipulates one variable, similar to an experiment

B

A researcher evaluates the effectiveness of an art class by having an art expert judge the quality of student's paintings at the beginning of the class, in the middle of the class, and at the end of the class. If the art expert's standards for judgment change during the class, then the internal validity of the study is threatened by ____ A. history B. instrumentation C. maturation D. regression toward the mean

B

A researcher is conducting an experiment comparing three treatment conditions. If the researcher uses a between-subjects design, there will ____ score(s) for each participant but if a within-subjects design is used there will be ____ score(s) for each participant. A. 1, 1 B. 1, 3 C. 3, 1 D. 3, 3

B

A researcher is trying to determine the best time of day for patients to take a cholesterol medication. A sample of men who have high cholesterol is divided into six groups. One group takes the medication every morning, a second group takes the medication at mid-day, and a third group takes the medication each night. There are also three control groups that receive a placebo instead of the real medication, one in the morning, one at mid-day, and one at night. If the results of the study show a 50-point main effect for the medication (men taking the medicine average 50 points lower cholesterol than men taking the placebo) and also show a significant interaction between medication and time of day, then what can the researcher conclude about the effect of the medication? A. The medication lowers cholesterol by around 50 points and it does not matter what time of day it is taken B. Although the average effect of the medication is to lower cholesterol by 50 points, the exact effect depends on what time of day it is taken C. Because there is an interaction, you cannot conclude that the medication has any effect on cholesterol D. None of the other options is an appropriate conclusion

B

Counterbalancing is used in A. between-subjects designs to reduce individual differences B. within-subjects designs to distribute order effects evenly across the treatment conditions C. between-subjects designs to distribute order effects evenly across the treatment conditions D. within-subjects designs to reduce the effects of reactivity

B

One of the primary advantages of a pretest-posttest nonequivalent control group design, in comparison to other nonequivalent group designs, is A. the posttest scores can help reduce threats from history effects B. the pretest scores can help reduce the threat of assignment bias C. the posttest scores can help reduce the threat of differential history D. the pretest scores can help reduce the threat of differential history

B

The appropriate hypothesis test for a within-subjects design that compares two treatment conditions is A. an independent-measures t test B. a repeated-measures t test C. a multi-group single-factor analysis of variance D. a chi-square test for independence

B

The basic threat to internal validity for a nonequivalent groups design is A. history B. assignment bias C. regression D. reactivity

B

The following data represent the means for each treatment condition in a two-factor experiment. What pattern of results is shown in the data? B1/A1=20, B1/A2=40, B2/A1=30, B2/A2=50 A. Main effects for both factors and an interaction B. Main effects for both factors and no interaction C. A main effect for factor A, no main effect for factor B, and no interaction D. A main effect for factor A, an interaction, but no main effect for factor B

B

What is the appropriate statistical analysis for evaluating the before treatment versus after treatment mean difference for a pretest-posttest design? A. independent-measures t test B. repeated-measures t test C. independent-measures analysis of variance D. repeated-measures analysis of variance

B

Which of the following correctly describes a research study comparing problem-solving ability for girls versus boys under three different levels of temperature? A. 2 x 2 design B. 2 x 3 design C. 2 x 2 x 2 design D. none of the above

B

Which of the following would allow a researcher to determine whether the treatment effects observe in a single-factor study would also be obtained with older participants? A. Add additional treatments to the original study B. Add age as a second factor to the original study C. Counterbalance the order in which different age groups are tested D. Limit the range of ages of participants to reduce the variance

B

A researcher is examining motor skill development by observing children at 18 months, 24 months, and 30 months. If the researcher uses a cross-sectional design and obtains 20 scores for each age, then how many children participated in the entire study? A. 20 B. 40 C. 60 D. Cannot determine without more information

C

A within-subjects design has a definite advantage over a between-subjects design when the number of available subjects is relatively ____ and individual differences are relatively ____ A. large, large B. large, small C. small, large D. small, small

C

How many different hypothesis tests (F-ratios) are contained in a two-factor ANOVA? A. 1 B. 2 C. 3 D. More than 3. The exact number depends on the number of levels for each factor

C

How many groups of participants would be needed to completely counterbalance a within-subjects experiment with three treatment conditions? A. 1 B. 3 C. 6 D. 9

C

In a time series design, the series of observations before treatment helps reduce threats to internal validity because A. a series of observations is more reliable than a single observations B. a series of observations has more validity than a single observation C. if an outside factor is influencing the scores, the effects should be seen before the treatment is administered D. if an outside factor is influencing the scores, it can be stopped before the treatment is administered

C

Order effects can be measured and evaluated with a ____ A. counterbalanced single-factor within-subjects design B. factorial design using a participant variable (such as age) as a second factor C. factorial design using the order of treatment as a second factor D. the other three choices can each be used to assess order effects

C

The primary problem with a cross-sectional developmental design is that differences between age groups may not be caused by age but rather are caused by A. history effects B. regression toward the mean C. cohort effects D. differential attrition

C

What is the appropriate statistical analysis for comparing mean differences for a differential design comparing samples representing three populations? A. independent-measures t test B. repeated-measures t test C. independent-measures analysis of variance D. repeated-measures analysis of variance

C

What name is given to the variable that is used to define the groups or conditions in a quasi-experimental study? A. independent B. dependent C. quasi-independent D. quasi-dependent

C

Which of the following is not an example of a nonexperimental or quasi-experimental study? A. a study comparing self-esteem scores for children with a learning disability versus scores for children without a learning disability B. a study comparing depression scores before therapy versus scores after therapy C. a study comparing performance in a room where the walls have been painted yellow versus performance in a room painted blue D. a study comparing attitude scores for men versus scores for women

C

A factorial study that measures depression before and after treatment for a treatment group and a control group is an example of a ____ A. between-subjects design B. within-subjects design C. repeated measures design D. mixed design

D

An advantage of a multiple-treatment within-subjects design compared to a two-treatment design is ____ A. there is a reduced risk of participant attrition B. there is a reduced risk that time-related factors will influence the data C. it is easier to counterbalance a design with several treatments D. it is more likely to reveal the full relationship between the independent variable and the dependent variable

D

Differential research is classified as A. correlational B. experimental C. quasi-experimental D. nonexperimental

D

If a researcher has a reason to expect large and long-lasting order effects, the best strategy is A. to increase the amount of time between treatment conditions B. to use partial counterbalancing C. to use complete counterbalancing D. to use a between-subjects research design

D

In a two-factor ANOVA, what is the implication of a significant A x B interaction? A. At least one of the main effects must also be significant B. Both of the main effects must also be significant C. Neither of the two main effects can be significant D. The significance of the interaction has no implications for the main effects

D

In a typical pre-post study A. two groups are measured before and after a treatment B. two groups are measured after a treatment C. one group is measured after a treatment D. one group is measured before and after a treatment

D

In a within-subjects design, individuals differences (participant variables) are a problem because A. they can become confounding variables B. they can increase the variability C. they can become confounding variables and they can increase variability D. individual differences are not a problem in a within-subjects design

D

The pretest-posttest control group design is an example of a A. between-subjects design B. within-subjects design C. repeated measures design D. mixed design

D

Which of the following differentiates a matched-subjects design from a within-subjects design? A. the matched-subjects design uses only one group of participants B. The matched-subjects design removes individual differences from the variance C. The matched-subjects design reduces the likelihood that individual differences can become a confounding variable D. The matched-subjects design uses a different group of participants for each treatment condition

D

Which of the following is an advantage of using gender as second factor in a study comparing two treatment conditions instead of using a mixed group of males and females in each treatment? A. The two-factor study would show how the treatments affect males and females separately B. The two-factor study would determine whether the treatment effect depends on gender C. The two-factor study could reduce variance if the scores for males are consistently higher or lower than the scores for females D. All of the other options are advantages of the two-factor study

D