front 1 - Apply the three criteria for establishing causation to
experiments and explain why experiments can support causal
claims.
| back 1 - Covariance
- study’s results can establish
this
- if independent variables did not vary, or if there is
no manipulating of the independent variable, then a study could
not establish covariance
- there is a need for comparison
groups
- Temporal Precedence
- The cause
variable precedes the effect variable
- Experimenters
manipulate the causal (independent) variable to ensure it comes
first
- Internal Validity
- to be
internally valid, a study must ensure that the causal variable and
not other factors are responsible for the change in the outcome
variable
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front 2 - Explain the difference between independent-groups and
within-groups designs, and the advantages and disadvantages of
each.
| back 2 -
independent group design
- experimental
design in which different groups of participants are exposed to
different levels of the independent variable for each participant
to experience only one level of the IV
- separate groups of
participants are placed into different levels of the independent
variable
- includes both the posttest-only design and the
pretest/posttest design
- disadvantage
- groups
can have extraneous differences (switch the disadvantage of
within-groups
- more participants and cost more
-
within-groups design
- each
participant is presented with all levels of the IV
- acted
on their own controls
- advantages -
- ensures
the participants in the two groups will be equivalent
- enables researchers to make more precise estimates of the
difference between conditions
- requires fewer
participants overall
- disadvantages
- repeated measure designs have the potential for order
effects, which can threaten the internal validity
- design may not be possible or practical
- when people
see all levels of the IV and then change how they normally
act
|
| back 3 - experimental design in which different groups of participants
are exposed to different levels of the independent variable for each
participant to experience only one level of the IV
- separate
groups of participants are placed into different levels of the
independent variable
- includes both the posttest-only design
and the pretest/posttest design
- disadvantage
- groups can have extraneous differences (switch the
disadvantage of within-groups
- more participants and cost
more
|
| back 4 - each participant is presented with all levels of the IV
- acted on their own controls
- advantages -
- ensures the participants in the two groups will be
equivalent
- enables researchers to make more precise
estimates of the difference between conditions
- requires
fewer participants overall
- disadvantages
- repeated measure designs have the potential for order effects,
which can threaten the internal validity
- design may not
be possible or practical
- when people see all levels of
the IV and then change how they normally act
|
front 5
Explain three potential threats to internal validity (design
confounds, selection effects, and order effects) in an experiment
and how to avoid them. | back 5 -
design confounds
- a threat to
internal validity in an experiment in which a second variable
happens to vary systematically along the IV
- an
alternative explanation for the results
- experimenter’s
mistake in designing the independent variable, carelessness
- ex. See if people write better on pink or green paper and
schedule the test at 8 am and one at 1 pm
-
selection effects
- occurs in an
independent design when the kinds of participants at one level of
the independent variable are systematically different from those
at the other level
- can be avoided → with random
assignment
- assignng participants at random to
different levels of the independent variable controls for all
sorts of potential selection effects
- order
effects
|
front 6
What is the difference between manipulated and measured
variables? Which are usually IVs and which are usually DVs? What is
an experimental condition? | back 6 - manipulated variable
- A variable in an experiment
that a researcher controls
- ex. assigning participants to
it’s different levels (values)
- usually the independent
variable
- measured variable
- a variable
in a study whose levels (values) are observed and recorded
- usually the dependent variable
- experimental
condition
- a study in which at least one variable is
manipulated and another is measured
|
front 7
Why is a comparison group so important in an experiment? | back 7 - a group in an experiment whose levels on the IV differ from
those of the treatment group in some intended and meaningful
way
- can see if there is a difference or a contrast
|
front 8 why is random assignment so important to an experiment? | back 8 - assigning participants to different experimental groups
- important b/c it controls for all sorts of potential selection
effects and a way of desystematizating the types of participants who
end up in each level of the IV
|
front 9 - What are some of the advantages to using a pretest, and what
are some of the disadvantages?
| back 9 - pretest
- participants are randomly assigned to at
least 2 groups and are tested on the key dependent variable twice
- once before and once after exposure to the IV
- advantages
- can be used when they want to make sure
random assignment made groups equal, enabling researchers to
track people’s change in performance over time (not seeing
change over time)
- similar to within-group
- looking for changed scores
- ex. seeing one
group change 1% or 10%
- disadvantages
- can be problematic
- informing what the
participants are doing in the test, can change the effect of the
study
- test with the Solomon test design
|
front 10 What is a repeated measures design within the within-groups design category? | back 10 participants respond to a dependent variable more than once, after
exposure to each level of the independent variable |
front 11
Why do researchers add (or combine) independent variables in a
factorial design? | back 11 - reason to combine independent variables in a factorial design
so you can study how they interact
- can measure whether the
results are consistent with the theory
|
| back 12 - a difference in difference
- results from a factorial
design in which the difference in the levels of one IV changes
depending on the level of the other IV
- the effect of one
independent variable depends on the level of the other independent
variable
|
front 13
Identify and interpret both main effects and interactions, and
explain the results in words. This looks a lot like the factorial
designs worksheet that I’ve given you. | back 13 - main effect: the overall effect of one independent variable on
the dependent variable, averaging over the labels of the other
independent variables
- ex. there is not a main effect
because the no difference in the marginal means OR There are main
effects because there is a difference in the marginal mean
*different enough, can be a small number, but be reasonable *
- provide a reasonable explanation
- interactions
- There is no interaction between the 2
variables because the lines are parallel
- There is an
interaction between the 2 variables because the lines are not
parallel
|
| back 14 - the overall effect of one independent variable on the dependent
variable, averaging over the labels of the other independent
variables
- ex. there is not a main effect because the no
difference in the marginal means OR There are main effects because
there is a difference in the marginal mean *different enough, can
be a small number, but be reasonable *
- provide a
reasonable explanation
|
| back 15 - There is no interaction between the 2 variables because the
lines are parallel
- There is an interaction between the 2
variables because the lines are not parallel
|
front 16
What does it mean to say that factorial designs can test
limits? Can test theories? | back 16 - To test limits means to test for moderators
- moderator: variable that changes the relationship between the
other two variables
- One can test theories by seeing
how variables interact and combine them in a factorial design. You
then measure whether or not the results are consistent with
this.
|
front 17
Explain independent-groups factorial design, within-groups
factorial design, and mixed factorial design. | back 17 - independent-groups factorial design
- both IVs are
studied as independent groups
- can be used as a
posttest-only design and pretest/posttest design
- within-groups factorial design
- each person is
presented with all levels of the independent variable
- randomly assigned
- mixed factorial design
- one independent variable is manipulated as independent
groups and the other is manipulated as within groups
- ex.
2 groups of people eat carbs & lift weights + aerobic, another
group would eat protein & lift weights + aerobic
- one
part is between groups and another part is within-group
|
front 18 independent-groups factorial design | back 18 both IVs are studied as independent groups
can be used as a posttest-only design and pretest/posttest design |
front 19 within-groups factorial designs | back 19 each person is presented with all levels of the independent variable
randomly assigned |
| back 20 - one independent variable is manipulated as independent groups
and the other is manipulated as within groups
- ex. 2 groups
of people eat carbs & lift weights + aerobic, another group
would eat protein & lift weights + aerobic
one part is
between groups and another part is within-group |
front 21
Why would we want to add levels to an independent variable? | back 21 - get info about, add more information about the independent
variable
- explain understanding of the relationship
- ex. to find food consumption on stress, you can choose
specifically what type of food (carbs & protein)
|
front 22 How do quasi-experiments differ from true experiments? Why does this
matter? Why would we use one? | back 22 differ from true experiments because the researchers do not have full
experimental control |
front 23
What are the main differences between small-N and large-N designs? | back 23 - Small-N designs focus on one or a few people in a study, gather
information from just a few cases
- Small-N designs
- each participant is treated separately in; small-N designs are
almost always repeated measures designs
- data for each
individual are presented
- careful designs enable us to
compare each individual during treatment periods and control
periods
|
front 24 Evaluate the design (stable baseline, multiple baseline, and
reversal) and results of small-N experiments to evaluate their support
for causal claims. | back 24 -
stable baseline: a study in which a practitioner or
researcher observes behavior for a baseline period before beginning
a treatment or other intervention
- make sure behavior
is stable
- result of small N experiments -
-
multiple baselines: researchers stagger their
introduction of an intervention across a variety of individuals,
times, or situations to rule out alternative explanations
- result of small N experiments -
-
reversal baseline: Researchers observe a problem
behavior both with and without treatment, but take away the
treatment for a while (the reversal period) *taking away treatment
can be caused by one of the threats * to see whether the problem
behavior returns (reverses)
- result of small N
experiments - enables a practitioner to evaluate the effectiveness
of a treatment, it may be considered harmful and unethical to
withdraw an effective treatment
|
| back 25 - a study in which a practitioner or researcher observes behavior
for a baseline period before beginning a treatment or other
intervention
- make sure behavior is stable
- result of small N experiments -
|
| back 26 - researchers stagger their introduction of an intervention
across a variety of individuals, times, or situations to rule out
alternative explanations
- result of small N experiments
-
|
| back 27 - Researchers observe a problem behavior both with and without
treatment, but take away the treatment for a while (the reversal
period) *taking away treatment can be caused by one of the threats *
to see whether the problem behavior returns (reverses)
- result of small N experiments - enables a practitioner to
evaluate the effectiveness of a treatment, it may be considered
harmful and unethical to withdraw an effective treatment
|
front 28
Explain what a nonequivalent control group interrupted
time-series design is. Why do we use them? | back 28 - interrupted time-series design: a quasi-experiment in which
participants are measured repeatedly on a dependent variable before,
during, and after the “interruption” caused by some event
- we use them to see if the independent variable changes
|
front 29 Explain why it is important that a study be replicable, and the
differences between direct replication, conceptual replication, and
replication-plus-extension (including when to use each). | back 29 - important to be replicable b/c you will be able to interrogate
statistical validity
- gives the study credibility and
important part of the scientific process
- Direct
replication
- Researchers repeat an original study as
closely as they can to see whether the effect is the same in the
newly collected data
- use this when you want to confirm
what you already know about the study
- Conceptual
Replication
- researchers explore the same research
question but use different procedures
- replication -
plus extension
- reserachers replicate their original
experimemt and add variables to test additional questions
|
| back 30 - Researchers repeat an original study as closely as they can to
see whether the effect is the same in the newly collected data
- use this when you want to confirm what you already know about
the study
|
| back 31 researchers explore the same research question but use different procedures |
front 32 replication - plus extension | back 32 researchers replicate their original experiment and add variables to
test additional questions |
front 33 Explain meta-analysis and why one would do one. | back 33 - what does the literature say about the topic?
- meta-analysis
- a way of mathematically averaging the
effect sizes of all the studies that have tested the same
variables to see what conclusions that whole body of evidence
supports
- one would do one b/c → to see the overall effect
size, can detect new patterns in literature, and test new
questions
|
front 34 Explain several of the considerations for when a study might or might
not need external validity (theory-testing or generalization modes). | back 34 - theory testing
- not need much external validity in
comparison to internal validity
- need to generalize when
testing theory
- researcher’s intent for a study, testing
association claims or causal claims to investigate support for a
theory
- generalization modes
- intent of
researchers to generalize the findings from the samples and
procedures in their study to other populations or contexts
- more concerned with external validity b/c they need to take in
samples with appropriate diversity of gender, age, ethnicity,
etc.
|
| back 35 - not need much external validity in comparison to internal
validity
- need to generalize when testing theory
- researcher’s intent for a study, testing association claims or
causal claims to investigate support for a theory
|
| back 36 - intent of researchers to generalize the finding from the
samples and procedures in their study to other populations or
contexts
- more concern with external validity b/c they need to
take in samples with appropriate diversity of gender, age,
ethnicity, etc.
|
front 37 Which of the three types of claims might be best tested in
generalization mode, and which in theory-testing mode? Why? | back 37 - theory-testing mode
- association claims
- casual claims
- Generalization mode
- frequency claims (always): representation samples are
important for supporting frequency claims
- association
(sometimes):
- casual (sometimes):
|