Ch. 10 Simple Experiments

Question 1

Comparison Group

Answer 1

A group in an experiment whose levels on the independent variable differ from those of the treatment group in some intended and meaningful way

Question 2

Control Group

Answer 2

No treatment condition

Question 3

Systematic Variability

Answer 3

A difference that could be attributed to a known factor (non-random)

Question 4

Unsystematic Variability

Answer 4

Differences are attributed to random fluctuations (maybe due to measurement error, etc.)

Question 5

Confound

Answer 5

a general term for a potential alternative explanation for a research findings; a threat to internal validity

Question 6

Design Confound

Answer 6

A threat to internal validity in an experiment in which a second variable happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results.

Question 7

Selection Effects

Answer 7

Participants are not chosen randomly

Question 8

Ways to Avoid Selection Effects

Answer 8

Random Assignment
Matched groups

Question 9

Independent-Groups Design

Answer 9

An experimental design in which different groups of participants are exposed to different levels of the independent variable, such that each participant experiences only one level of the IV.

Question 10

Within-Groups Design

Answer 10

An experimental design in which each participant is presented with all levels of the IV.

Question 11

Repeated-Measured Design

Answer 11

Subjects measured more than once; after each exposure to each level of the IV

Question 12

Concurrent-Measures Design

Answer 12

Subjects exposed at different levels of the IV at the same time

Question 13

Advantages of Within-Groups

Answer 13

Participants in your groups are equivalent because they are the same participants and serve as their own controls

Within-groups designs require fewer participants than other designs

Question 14

Order Effects

Answer 14

A threat to internal validity in which exposure to one condition changes participant responses to a later condition

Question 15

Practice Effect

Answer 15

Participants performance improves over time because they become practiced at the dependent measure

Question 16

Carryover Effect

Answer 16

Some form of contamination carries over from one condition to the next.

Question 17

Fatigue Effect

Answer 17

Degrades over time because they become tired, not because of the manipulation of treatment

Question 18

Counterbalancing

Answer 18

In a repeated-measure experiment presenting the levels of the IV to participants in different sequences to control for order effect.

Question 19

Full Counterbalancing

Answer 19

All possible condition orders are represented

Question 20

Partial Counterbalancing

Answer 20

Some, but not all, of the possible condition orders are represented

Question 21

Disadvantages of Within-Groups

Answer 21

Potential for order effect

Might not be practical or possible

Experiencing all levels of the IV changes the way participants act (demand characteristics)

A cue that leads participants to guess a study’s hypotheses or goals

A threat to internal validity

Question 22

Posttest-Only Design

Answer 22

Using an independent-group design in which participant are tested on the dependent variable only once

Question 23

Pretest/Posttest Design

Answer 23

Using an independent-group design in which participant are tested on the key dependent variable twice: once before and once after exposure to the IV.

Question 24

Manipulation Checks

Answer 24

An extra DV researchers can include to determine how well a manipulation worked

Question 25

Pilot Studies

Answer 25

A study completed before or sometimes after the study of primary interest, usually to test the effectiveness or characteristics of the manipulation