Chapter 9: Independent-Groups Designs & Inferential Statistics Flashcards
What is poor internal validity?
An experiment has poor internal validity when you cannot say with certainty that the manipulation of the IV was what caused any observed differences in the DV
Possible confound: maturation
Treatment group/groups improve only because of the passing of time
Possible confound: regression of the mean
Post-test scores are normal/average because the pre-test scores are extremely low or high
Possible confound: mortality or attrition
Losing participants
What is external validity?
(Also known as ecological validity) refers to the ability to generalize the results of the experiment beyond the specific participant and laboratory setting
What test statistic is used for independent groups?
Between-subjects t test: can be used to determine if the numerical difference between the means of two treatment conditions is statistically significant