Chapter 9: Independent-Groups Designs & Inferential Statistics

Question 1

What is poor internal validity?

Answer 1

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

Question 2

Possible confound: maturation

Answer 2

Treatment group/groups improve only because of the passing of time

Question 3

Possible confound: regression of the mean

Answer 3

Post-test scores are normal/average because the pre-test scores are extremely low or high

Question 4

Possible confound: mortality or attrition

Answer 4

Losing participants

Question 5

What is external validity?

Answer 5

(Also known as ecological validity) refers to the ability to generalize the results of the experiment beyond the specific participant and laboratory setting

Question 6

What test statistic is used for independent groups?

Answer 6

Between-subjects t test: can be used to determine if the numerical difference between the means of two treatment conditions is statistically significant