Term
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Definition
an event occuring between pretest and posttest other than the independent variable that could affect the dependent variable |
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| changes occur in participants because of passage of time |
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Term
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Definition
| taking a pretest somehow affects the taking of the posttest |
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Definition
| instuments are not accurate/precise enough or do not measure what they are supposed to measure |
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Term
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Definition
| participants selected in a non-random manner differ in some way |
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Definition
| extremely high or extremely low scores regress toward mean |
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| participants frop out of the study or cannot be located |
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Definition
| altered behavior due to the effects of being studied and observed |
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Definition
| altered behavior because of expectations |
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Definition
| treatment of experimental group spills over to comparison or control groups |
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Definition
| the location of program or data collection affects participant responses |
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| dfferenced in persons presenting a program affect the program |
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Definition
| exists if the observed effect of the independent variable on the dependent variable are real and not caused by extraneaous factors |
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Definition
| concerned with the ability to generalize the study results to other froups and settings beyond those in the current experiment |
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Term
| selection treatment interaction |
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Definition
| this threat concerns the ability of a reseracher to generalize the results of the study beyond the groups involvement in the study |
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Term
| setting treatment interaction |
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Definition
| this threat concerns the extent to which the envornmental conditions or setting under which an experimental study was conducted can be duplicated in other settings |
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Term
| history treatment interaction |
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Definition
| this threat to external validity develops when the reseracher tries to generalze finding to past and future situations |
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Term
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Definition
| ANCOVA can be used to wualize many initial diffeerence that might exist between groups |
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