Introduction to Experimental Research

Question 1

Independent variable

Answer 1

the variable being controlled/ manipulated by the researcher

Question 2

Extraneous variables

Answer 2

variables that are not of interest to the researcher so they must be held constant as to not influence results

Question 3

Dependent variable

Answer 3

behaviours being measured

Question 4

All manipulated independent variables must have a minimum of ___ levels

Answer 4

two

Ex; two dosage levels of caffeine in order to make a comparison between the effects of caffeine and reaction time

Question 5

Independent variables that are manipulated in a study tend to fall into three somewhat overlapping categories:

Answer 5

1. Situational
2. Task
3. Instructional

Question 6

Situational variables

Answer 6

Features in the environment that participants might encounter

Ex; in a helping behaviour study, the researcher interested in studying the effect of the number of bystanders on the chances of help being offered might create a situation in which subjects encounter a person in need of help

Question 7

Task variables

Answer 7

Problems to solve

Ex; research on the psychology of reasoning often involves giving people different kinds of logic problems

Question 8

Instructional variables

Answer 8

Manipulated by telling different groups to perform a particular task in different ways

Ex; students in a memory task who are all shown the same list of words might be given different instructions about how to memorize the list

Question 9

Confound

Answer 9

Any uncontrolled extraneous variable that co-varies with the independent variable

Question 10

Two major problems that can occur with poorly chosen dependent variables:

Answer 10

1. Ceiling effect

2. Floor effect

Question 11

Ceiling effect

Answer 11

When the average scores for the groups in the study are so high that no difference can be determined between conditions

This can happen when your dependent measure is so easy that everyone gets a high score

Question 12

Floor effect

Answer 12

Happens when all the scores are extremely low

This usually happens because the task is too difficult for everyone

Question 13

Subject variables

Answer 13

Already existing characteristics of the individuals participating in the study (age, gender, SES)

Question 14

To judge whether change occurred one procedure is to evaluate people prior to the experience with a _______ then follow with a _____

Answer 14

pretest, posttest

Question 15

Regression to the mean

Answer 15

Refers to the fact that if the first score from a subject is an extreme score, then the second or third score from the same person will be closer to whatever the mean is for the larger set of scores

Question 16

Attrition

Answer 16

Participants don’t always complete the experiment they begin

Question 17

Why is attrition a problem?

Answer 17

If particular types of people are more likely to drop out than others, then the group finishing the study is made up of different types of people than the group that started

Question 18

The X is what Woodworth called the _________ ________

Answer 18

independent variable

Question 19

The independent variable is sometimes called the __________ variable

Answer 19

manipulated

Question 20

Statistical conclusion validity

Answer 20

the extent to which the researcher uses statistics properly to draw an appropriate conclusion

Question 21

If the dependent measures are not reliable, there will be a great deal of error validity. What type of error would occur?

Answer 21

Type II error

Question 22

Construct validity

Answer 22

Whether a test truly measures some construct and thus refers to the adequacy of operational definitions

Question 23

External validity

Answer 23

Degree to which research findings generalize beyond the laboratory (to other populations, to other environments, and to other times)

Question 24

Ecological validity

Answer 24

Subtype of external validity. Degree to which research findings can be generalized to real life settings

Question 25

Internal validity

Answer 25

Degree to which an experiment is methodologically sound and confound-free

Question 26

3 threats to internal validity

Answer 26

1. History and maturation
2. Regression to the mean
3. Testing and instrumentation