Term
| Sources of Selection Bias |
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Definition
- Self-Assignment to group produces selection bias
- Researcher assignment to group produces selction bias
- Arbitrary assignment to group produces selction bias
- Choosing groups based on their differences results in having groups that are different
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Term
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Definition
| error in choosing individuals when doing a study |
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Term
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Definition
Identical participants do not exist.
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Term
| Problems with having matching groups on every relevant variable |
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Definition
| too many relevant variables and we don't know what the relevant variables are |
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Term
| Problems with the pretest-posttest design (3 reasons) |
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Definition
| Maturation, History, and Testing |
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Term
| What is maturation in terms of change between pretest and posttest? |
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Definition
| Natural physiological changes within the participant may change the participant's behavior |
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Term
| What is history in terms of change between pretest and posttest? |
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Definition
| the treatment may not be the only thing in the participant's enviornment that changes |
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Term
| What is testing in terms of change between pretest and posttest? |
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Definition
| measuring participants changes participants |
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Term
| How measurement changes may cause changes in scores in pretest and posttest |
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Definition
instrumentation: changes in how participants are measured
Regression revisited: Extreme pretest scores may lead to less extreme posttest scores
mortality: changes in how many participants are measured |
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Term
| What is the relationship between internal and external validity |
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Definition
attempts to rule out threats to internal validity may hurt external validity
internal and external validity are not completely incompatible |
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Term
| Participant characteristics |
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Definition
| aspects of the participant, such as age, sex or personality traits, that are treated as if they are IV's |
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Term
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Definition
uncontrolled variables that can cause unintended changes between groups
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Term
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Definition
| a situation in which the results could of occured because of another variable within the study |
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Term
| should you record more than one DV? |
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Definition
| if you have the measurement capabilities, there is nothing to prohibit the recording of more than one DV |
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Term
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Definition
| unwanted variables that can cause the variability of scores within groups to increase |
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Term
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Definition
randomization
elimination
constancy
balancing - a control procedure that chieves group equality by distributing extraneous variables equally to all groups |
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Term
protecting internal validity...
How important is internal validity? |
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Definition
1. Detect threats to internal validity
2. avoid using design that's vulnerable to threat
3. to stepts to elimate |
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Term
| Broad categories of threats to validity |
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Definition
People are different
people change
the process of studying people changes people |
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