Exam 3 psy-260

How many steps are there to determine mediation?

5

spurious association

A bivariate association that is attributable only to systematic mean differences on subgroups within the sample; the original association is not present within the subgroups.

Compare third variables and mediating variables

A moderator is kind of interesting—it means your correlation is there in one group, but not the other.  However, a third variable is a problem if you want to make a claim that A and B are correlated—it means your correlation isn't really "there" at all.

Describe the purpose of Control Variables

A potential variable that an experimenter holds constant on purpose.

What design is used to address possible selection effects?

A pre-test/posttest design, because the groups are usually smaller, so it is easier to tell if they are lopsided

third variable problem

A problem that occurs when the researcher cannot directly manipulate variables; as a result, the researcher cannot be confident that another, unmeasured variable is not the actual cause of differences in the variables of interest.

Outliers

A score that stands out as either much higher or much lower than most of the other scores in a sample

restriction of range

A situation involving a bivariate correlation, in which there is not a full range of possible scores on one of the variables in the association, so the relationship from the sample underestimates the true correlation.

Multivariate Design

A study designed to test an association involving more than two measured variables

Describe the purpose of Manipulated Variables

A variable in an experiment that a researcher controls, such as by assigning participants to its different levels (values)

Describe the purpose of Measured Variables

A variable in an experiment whose levels (values) are observed and recorded

Mediators

A variable that helps explain the relationship between two other variables

Describe the purpose of Independent Variables

A variable that is manipulated in an experiment. In a multiple-regression analysis, a predictor variable used to explain variance in the criterion variable

Bivariate Correlations

An association that involves exactly two variables

What Factors influences statistical significance?

Effect size and sample size

Dr. Kline, an environmental psychologist, conducts a survey to examining whether visiting zoos causes people to have more positive attitude toward environmental conservation. He asks a group of 45 people attending the zoo on Saturday morning about their attitudes. He finds that 69% of the people report having a positive attitude after their visit. What is NOT true of Dr. Kline's study?

He does not have a dependent variable

What is the main priority for experimental studies?

INTERNAL VALIDITY

Autocorrelation

In a longitudinal design, the correlation of one variable with itself, measured at two different times.

Describe the purpose of Dependent Variables

In an experiment, the variable that is measured. In a multiple-regression analysis, the single outcome, or criterion variable, the researchers are most interested in understanding or predicting

Moderators

Is a variable the changes the relationship between two other variables

random selection

Randomly gathering a representative sample for a study by identifying a population and randomly selecting people from that population

Effect Size

The magnitude, or strength, of a relationship between two or more variables

Which of the following is NOT true of selection effects?

They are unimportant for interpreting internal validity

Which of the following is NOT true of third variables and mediating variables?

Third variables can be detected using multiple regression techniques, but mediating variables cannot.

Why do experiments utilize random assignment?

To avoid selection effects; keeps the groups fair as far as intelligence, motivation, etc. goes

Are there cases in which reporting a small effect would be important?

Yes because a very small effect size will be statistically significant if it is identified in a very large sample

Latin square

a formal system to ensure that every condition appears in each position at least once

comparison group

a group in an experiment whose level on the independent variable differs from those of the treatment group in some intended and meaningful way

directionality problem

a problem encountered in correlational studies; the researchers find a relationship between two variables, but they cannot determine which variable may have caused changes in the other variable

t-test

a statistic that compares two means to see whether they could come from the same population

multiple regression

a statistical technique that computes the relationship between a predictor variable and a criterion variable, controlling for other predictor variables

counterbalancing full

all possible condition orders are represented

confound

alternative explanations

curvilinear association

an association between two variables which is not a straight line; instead, as one variable increases, the level of the other variable increases and then decreases (or vice versa)

Independent groups design

an experimental design in which different groups of participants are exposed to different levels of the independent variable, such that each participant experiences only one level of the independent variable

within-groups design

an experimental design in which each participant is presented with all levels of the independent variable

random assignment

assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups

order effects

being exposed to one condition changes how participants react to the other condition.

Explain multiple regression designs

can help rule out some third variables, thereby addressing some internal validity concerns.

Running two experiments at the same time is:

concurrent measure design

demand characteristics

cue that can lead participants to guess an experiment's hypothesis

Dr. Acitelli was concerned that asking participants how long it took them to fall asleep would lead to suspect that was the purpose of the study. Her decision to measure how long it took participants to go to sleep using the EEG instead of self report was meant to decrease which of the following?

demand characteristics

design confound

experimenter's mistake in designing the independent variable

Dr. Losbury is doing a follow up study in which instead of asking participants to listen to music to induce mood, she has them write either a story about a character who just won the lottery or a story about a character who just experienced death of their spouse. This change in the mood variable is designed to enhance the study's

external validity

Random selection enhances _______ and random assignment enhances________

external, internal

manipulation check

extra dependent variable that researchers can insert into an experiment to convince them that their experimental manipulation worked

treatment group

group being studied that receives a treatment

control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment

systematic variability

in an experiment, the levels of a variable coinciding in some predictable way with experimental group membership, creating a potential confound

unsystematic variability

in an experiment, when levels of a variable fluctuate independently of experimental group membership, contributing to variability within groups

predictor variable

independent variable

All of the following are advantages of within-groups designs EXCEPT:

it is less time consuming for the participants

practice effects (fatigue effects)

long sequence might lead participants to get better at the task, or to get tired or bored toward the end

Which of the following research designs is used to address possible selection effects?

matched groups design

If a researcher is asking why the relationship exists she is curious about which of the following?

mediation

carryover efect

ome form of contamination carries over from one condition to the next

partial counterbalancing

only some of the possible condition orders are represented

pretest-posttest design

participants are randomly assigned to at least two different groups and are tested on the key dependent variable twice—once before and once after exposure to the independent variable

posttest-only design

participants are randomly assigned to independent variable groups and are tested on the dependent variable once

Which of the following is a threat to internal validity found within groups designs but not in independent designs?

practice effects

counterbalancing

present the levels of the independent variable to participants in different sequences

Longitudinal Design

provide evidence for temporal precedence by measuring the same variables in the same people at several points in time. Longitudinal research is used in developmental psychology to study changes in a trait or an ability as a person grows older. In addition, this type of design can be adapted to test causal claims.

Statistical Significance

refers to the conclusion a researcher reaches regarding the likelihood of getting a correlation of that size just by chance, assuming there's no correlation in the real world.

power p

refers to the probability that a study will show a statistically significant result when an independent variable truly has an effect in the population.

longitudinal design

research design in which one participant or group of participants is studied over a long period of time

What is the pattern and parsimony approach to causation?

researchers can investigate causality by using a variety of correlational studies that all point in a single, causal direction.

parsimony

scientific theory provides the simplest explanation of some phenomenon

Experiments use random assignment to avoid which of the following?

selection effects

cross-lag correlations

show whether the earlier measure of one variable is associated with the later measure of the other variable

Describe internal validity threats to within groups design and independent groups design

testing, instrumentation

selection effect

the kinds of participants in one level of the independent variable are systematically different from those in the other

criterion variable

the variable in a multiple-regression analysis that the researchers are most interested in understanding or predicting

Which of the following is NOT a disadvantage of within-groups designs?

these designs rely on fewer participants

cross sectional correlation

they test to see whether two variables, measured at the same point in time, are correlation

Which of the following is NOT a reason that a researcher might choose a pretest/post-test design? a. to ensure that random assignment made the treatment/comparison groups equal

to allow for the study of spontaneous behavior

pilot study

using a separate group of participants, that is completed before (or sometimes after) conducting the study of primary interest

Using a matched group design is especially important in which of the following cases?

when you have only a few participants