Ch 9: Intro to Simple Experiments

Question 1

between-subjects designs

Answer 1

an experimental design in which different groups pf participants are exposed to different levels of the independent variable such that each participant experiences only one level of the independent variable

Question 2

carryover effects

Answer 2

a threat to internal validity that occurs when being exposed to one condition changes how people react to a later condition

Question 3

concurrent-measures designs

Answer 3

an experiment using a within-groups design in which participants are exposed to all the levels of an independent variable at roughly the same time, and a single attitudinal or behavioral preference is the dependent variable

Question 4

condition

Answer 4

one of the levels of the independent variable in an experiment

Question 5

confounds

Answer 5

a potential alternative explanation for a research finding (a threat to internal validity)

Question 6

control group

Answer 6

a level of an independent variable that is intended to represent “no treatment” or a neutral condition

Question 7

control variable

Answer 7

a potential variable that an experimenter holds constant on purpose

Question 8

counterbalancing

Answer 8

presenting the levels of the independent variable to participants in different orders to control for order effects

Question 9

demand characteristics

Answer 9

cues that lead participants to guess a study’s hypotheses or goals

Question 10

dependent variable

Answer 10

in an experiment, the variable that is measured, or the outcome variable

Question 11

design confound

Answer 11

a second variable that happens to vary systematically along with the independent variable and therefore is an alternative explanation for the results

Question 12

independent variable

Answer 12

a variable that is manipulated in an experiment

Question 13

independent-groups design

Answer 13

an experimental design in which different groups pf participants are exposed to different levels of the independent variable such that each participant experiences only one level of the independent variable

Question 14

Latin square

Answer 14

a formal system of partial counterbalancing that ensures that each condition appears in each condition at least once

Question 15

manipulation checks

Answer 15

an extra dependent variable that researchers can include in an experiment to determine how well an experimental manipulation worked

Question 16

matched-groups design

Answer 16

an experimental design in which participants who are similar on some measured variable are grouped into sets and the members of each matched set are then randomly assigned to different experimental conditions

Question 17

order effects

Answer 17

a threat to internal validity that occurs when being exposed to one condition changes how people react to a later condition

Question 18

partial counterbalancing

Answer 18

a method of counterbalancing in which some, but not all, of the possible condition orders are represented

Question 19

pilot study

Answer 19

a study completed before (or sometimes after) the study of primary interest, usually to test the effectiveness or characteristics of the manipulations

Question 20

placebo group

Answer 20

a control group that is exposed to an inert treatment (ex: sugar pill)

Question 21

posttest-only design

Answer 21

an experiment with an independent groups design in which participants are tested on the dependent variable only once

Question 22

power

Answer 22

the probability that a study will show a statistically significant result when some effect is truly present in the population

Question 23

practice effects

Answer 23

a type of order effect in which people’s performance improves over time because they become practiced at the dependent measure (not because of the manipulation or treatment)

Question 24

pretest/posttest design

Answer 24

an experiment with an independent-groups design in which participants are tested on the key dependent variable twice- once before and once after exposure to the independent variable

Question 25

random assignment

Answer 25

the use of a random method (ex: flipping a coin) to assign participants into different experimental groups)

Question 26

repeated-measures design

Answer 26

an experiment with a within-groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent variable

Question 27

selection effect

Answer 27

a threat to internal validity that occurs when the kinds of participants at one level of the independent variable are systematically different from those at the other level of the independent variable

Question 28

systematic variability

Answer 28

in an experiment, the situation that occurs when the levels of a variable coincide in some predictable way with experimental group membership, creating a potential confound

Question 29

treatment group

Answer 29

the participants in an experiment who are exposed to the level of the independent variable that involves a drug, therapy, or intervention

Question 30

unsystematic variability

Answer 30

in an experiment, the levels of a variable occurring independently of experimental group membership, contributing to variability within groups

Question 31

within-groups design

Answer 31

a study design in which each participant is presented with all levels of the independent variable