Chap 12

Question 1

Define nonequivalent control group design

Answer 1

A quasi-experimental study that has at least one treatment group and comparison group, but participants have not been randomly assigned to the two groups

(Groups are not perfectly equivalent)

(Ex: head start program children vs non head start children)

Question 2

Repeated measures: quasi-experiments

Answer 2

Participants experience both levels of an independent variable

Question 3

Define interrupted time-series design

Answer 3

A quasi experimental study that measures people repeatedly on a dependent variable before, during and after the “interruption” caused by some event

(Ex: vacation and job burn outs, tested before during and after vacation)

Question 4

Define quasi-experiments

Answer 4

Similar to true experiments except experimenters don’t have full experimental control

Question 5

Define nonequivalent groups interrupted time-series design

Answer 5

It combines two of the previous studies (nonequivalent control group and interrupted time-series)

One treatment group and comparison group (without treatment) and tested multiple times throughout study

Question 6

What’s the main problem with quasi-experiments?

Answer 6

Internal validity: the researchers ability to draw causal conclusions from the results

We’re there alternate explanations for your findings?

Question 7

Selection effects are relevant for which group design

Answer 7

Independent group designs

Question 8

When does a selection threat to internal validity apply

Answer 8

When the groups at the various levels of an independent variable contain different types of participants

This makes it unclear whether it was the independent variable or the different type of participants in each group that led to a difference in the dependent variable between the groups

Question 9

Define maturation threats

Answer 9

When and experiment or quasi-experimental design has a pretest and post test and a treatment group that shows an improvement over time but it is not clear whether the improvement was caused by the treatment or whether the group would’ve improved spontaneously or even without the treatment

(Comparison groups help rule these out)

Question 10

Define history threat

Answer 10

Occurs when external historical events happen for everyone in a study at the same time as the treatment variable or by the common external event.

(Comparison groups help rule these out)

Question 11

Define selection history threat

Answer 11

History threat that applies to only one group not the other

Historical event systematically affects the subjects only in the treatment groups or in the comparison group not both

Question 12

Define regression to the mean

Answer 12

Occurs when an extreme score is caused by a combination of random factors that are unlikely to happen in the same combination again so the extreme score gets less extreme overtime

(Ex: Phillies lucky 22-1 win over the Reds, did not repeat itself in the next game)

Could be just luck, and luck changes over time

Regression effects are a threat to validity primarily when a group is selected because of its extremely high or low scores.

Question 13

Define attrition (mortality) threat

Answer 13

Applies when people drop out of a study for some systematic reason.

Occurs mainly in designs with protest and post test

(To check for you should only count people who complete all parts of study)

Question 14

Define testing threats

Answer 14

Can occur whenever researchers measure participants more than once.

A testing threat is a kind of order fact in which participants tend to change as a result of having been test before

Repeated testing my cause people to improve regardless of the treatment they received

It can also cause people to decline because of fatigue or boredom

Question 15

Define instrumentation threats

Answer 15

Can be an internal validity threat when participants are tested or observed twice

A measuring instrument to change over repeated uses and this change to threaten internal validity

(Ex: study uses two versions of a test with different standards)

Comparison group can help rule this out

Question 16

Define observer bias

Answer 16

When the experimenters expectations influence their interpretation of the results

To check: Was the study double blind?

Question 17

Define experimental demand

Answer 17

And participants guess with the study is about and change their behavior in the expected direction

To check: you can think about whether the participants were able to detect the study’s goals and respond accordingly

Question 18

Define placebo effect

Answer 18

When the participants improve but only because they believe they’re receiving an effective treatment

To check: comparison group that received inert, placebo, or treatment

Question 19

Why do we do quasi-experiments

Answer 19

Opportunity: take advantage of real-world opportunities

External validity: enhances external validity. We don’t have to question real world setting because it did (not manipulated)

Ethics: not withholding treatment or benefits it happens on it’s own

Construct validity: how well study is manipulated or measured

Statistical validity: how large the groups differences were (the effect size) and whether the results were statistically significant

Question 20

How are quasi-experiments and correlation all studies different and the same

Answer 20

Same: not randomly assigned, 2 measured variables

Different: in quasi-experiments researchers tend to do more meddling

Question 21

Define small-N design

Answer 21

Obtain a lot of info from a few cases

Each participant is treated as a separate experiment.

Almost always repeated measures design in which researchers observe how the person or animal response to several systematic design conditions.

Individuals data are presented

Researchers decide whether result is replicated by repeating our experiment on a new participant

Question 22

Define large-N designs

Answer 22

Participants are grouped. The data from an individual participant are not of interest to themselves; data from all participants in each group are combined and studied together.

Dara are represented as group averages

Researchers decide whether a result is replicated by doing a test of statistical significance

Question 23

Define single-N design

Answer 23

Restricting the study to only one animal or person

Question 24

Define experimental control

Answer 24

What the experimenter controls

Question 25

Manipulation

Answer 25

The task given

Ex: strong manipulation task would be easy for someone and difficult for someone else

Question 26

Define replication

Answer 26

Repeating the study

Question 27

Define study special cases

Answer 27

Takes advantage of a unique population

Just as a quasi-experiment it can take advantage of natural accidents laws and historical events

Question 28

Are the disadvantages of small-N studies

Answer 28

Few participants might not represent the human population very well

May not be ethical to test on more people in some cases

Question 29

What are the three small-N designs

Answer 29

Stable-baseline design: researchers spent in several weeks recording baseline information, then taught new strategy/given treatment

The stable baseline meant that there was not a single extremely low point for much improvement would almost definitely occur

Question 30

Define multiple-baseline design

Answer 30

First recorded a baseline of multiple behaviors

Overcorrection was applied to one behavior and then later extended to other behaviors

Question 31

Define reversal designs

Answer 31

Researchers observe a problem behavior both with and without treatment

Reversal designed the practitioner takes the treatment away for a while the (reversal phase) to see whether the problem behavior returns

If the treatment was really working then the behavior should worsen again when the treatment is discontinued