PSY 240 CH 9-11

Compare multilple groups by using a ___-___ design

More than two ___ ___ are needed to accurately compare multiple effects

We need to see the full shape of the graph in order to determine the ___ ___

A manipulation's construct validity is weakened by ___ variables

A group that recieves no treatment - not even a placebo

a treatment that has no effect

When group means are further apart, there is greater ___

ANOVA

Allows us to compare between-groups variance to with-groups variance

the ratio of the between-groups variance to the within-groups variance

Our environment varies in ___ and to ___ ___ a variable is present

level of a variable

Finding the functional relationship requires ___ more than 2 data points

To make accurate statements regarding effects we need to know the ___ ___ of the IVs and DVs

Multilevel experiments means greater ___ and ___ due to ___ ___

variables are ___ confounded

___ ___ experiments are stronger than the simple experiment

in Multiple Group experiments, ___ validity is improved and we are able to map ___ relationships

Determine the ___ we will use BEFORE the type of Design

Type of analysis used will influence (3)

To find a treatment effect, we look for ___

difference among group means

A ___ difference between means is most likely due to chance

A ___ difference between means is likely due to the effect of the treatment

Within-group variability is NOT due to ___

Within-group variability is due to ___ ___

Between-groups variability is due to ___ and ___ ___

the effects of random error

the effects of random error plus any treatment effects

Effects of random error (3)

tells us the extent to which chance caused individual scores to differ from each other

tells us the degree to which our groups actually vary from one another

Two factors affect the extent to which group means differ

In an ___, we see any possible effects of individual IVs and ALSO any interaction effects between the variables

We can ask more refined questions in a ___ ___ experiment

factors other than the treatment

We can eliminate extraneous factors by using a ___-___ or the ___/___ design

If groups differ before the treatment, differences in scores could be due to ___ ___ which threatens ___ validity

By using ___, groups should have nearly identical characteristics

groups are the same on the pretest, but develop at different rates

Average scores tend to become less extreme at the ___

tells us that extreme scores will revert back to more normal levels on retest

Groups may also end up being different due to ___ - when participants drop out of a study

use the same participants in the no-treatment group and the treatment group.  This approach uses the ___-___ design

Participants may change because of ___.  A change in a participant's environment has a ___ effect on their scores.

when participants become better at taking our test due to practice resulting in ___ ___

changes in the measuring scale resulting in changes in scores

Any change in the cause must be reflected by change in the ___

Differences in the ___ variable must be reflected by a change in the ___ variable

changes in the ___ occured before changes in the ___

Experimental design where everything is identical for both treatment groups, except that one group recieves the treatment

Group scores are compared

8 Threats to internal validity

- groups were different to begin with

8 Threats to internal validity

- groups were destined to grow in different ways

8 Threats to internal validity

- extreme pretest scores tend to normalize

8 Threats to internal validity

- participants drop out

8 Threats to internal validity

- natural growth and development appear at treatment effects

8 Threats to internal validity

- changes in environment caused changes in participants

8 Threats to internal validity

- practice on the pretest caused changes in posttest scores

8 Threats to internal validity

- the questionnaire changed between pre- and posttest

Arbitrary assignment to groups and when participants choose in which group they want to be.

These individuals are different!!!

Measurements are only as accurate as the ___

Using unreliable tools produces ___ ___

Group's averages tend to become less extreme during the ___

scores that are extreme will revert back to more normal levels at the retest

Design used to determine: Why people behave the way they do and How we can help them behave differently

Design used to isolate underlying causes:

Requires internal validity (cause and effect)

In a simple experiment, groups must NOT differ ___.

One group will receive treatment and the other will not.

In a simple experiment, treatments can involve different ___ and ___ of activity

To ensure that the treatment is the only difference between groups of a simple experiment, we use ___ ___

In a simple experiment, we test the experimental hypothesis against the ___ ___

Hypothesis that states that the treatment WILL HAVE an effect

Larger groups tend to be more ___, and effects will stand out better

we need to know the scores of our Dependent variable to be able to calculate any ___ ___ of our Independent variable 

If a difference is ___, we can be certain, beyond a reasonable doubt, that the difference is NOT due to ___

With a ___ ___ error, we state that a difference between our groups was Significant when it was NOT

With a ___ ___ error, we state that a difference between our groups was NOT significant, but due to Chance, when it actually WAS significant

To avoid Type 2 errors

We need enough ___ to detect true Differences

Participants who are similar

___ limits random error from disguising our treatment effect

Power -

Increase the ___ of our treatment effect

We use the ___ ___ to see whether the difference between Mean group Averages is big enough NOT to be due to random error.