8 classes of extraneous variables (threat to internal validity)

Question 1

what are the 8?

Answer 1

1- History
2- Maturation
3- Testing
4- Instrumentation
5- Statistical Regression
6- Biases in selection
7- Experimental mortality
8- Selection-maturation interaction`

Question 2

History:

Answer 2

the specific events occurring between the first and second measurement in addition to the experimental variable

Question 3

Maturation:

Answer 3

processes within the respondents operating as a function of the passage of time per se, including growing older, hungrier, more tired, etc.

Question 4

Testing:

Answer 4

the effects of taking a test upon the scores of a second testing

Question 5

Instrumentation:

Answer 5

changed in the calibration of a measuring instrument or changes in the observers or scorers used may produce changes in the obtained measurements

Question 6

Statistical regression

Answer 6

groups have been selected on the basis of their extreme scores

Question 7

Biases in selection:

Answer 7

differential selection of respondents for the comparison groups

Question 8

selection-maturation interaction

Answer 8

certain of the multiple-group quasi-experimental designs is confounded with the effect of the experimental variable.

Question 9

Factors jeopardizing external validity: (4)

Answer 9

the reactive or interaction effect of testing

the interaction effects of selection biases and the experimental variable

reactive effects of experimental arrangements

multiple-treatment interference