chapter 10-11 vocab terms

Question 1

manipulated variable

Answer 1

variable in an experiment that a researcher controls such as assigning participants to different levels (values) (independent)

Question 2

measured variables

Answer 2

a variable in a study whose levels are observed and recorded (dependent)

Question 3

condition

Answer 3

one of the levels of the independent variable in an experiment

Question 4

control variable

Answer 4

a variable that a researcher holds constant on purpose

Question 5

comparison group

Answer 5

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 6

control group

Answer 6

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

Question 7

placebo group

Answer 7

a control group in an experiment that is exposed to an inter treatment

Question 8

confound

Answer 8

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

Question 9

design confound

Answer 9

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

Question 10

systematic variability

Answer 10

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

Question 11

unsystematic variability

Answer 11

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

Question 12

selection effect

Answer 12

a threat to internal validity that occurs in an independent groups design when the kids of participants at one level of the independent variable are systematically different from those at the other level

Question 13

random assignment

Answer 13

the use of a random method to assign participants to diff experimental groups

Question 14

matched groups

Answer 14

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

Question 15

treatment group

Answer 15

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

Question 16

independent-groups design

Answer 16

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 independent variable.
Also called between-subjects design, between-groups design

Question 17

within-groups design

Answer 17

An experimental design in which each participant is presented with all
levels of the independent variable. Also called within-subjects design.

Question 18

posttest-only design

Answer 18

An experiment using an independent-groups design in which
participants are tested on the dependent variable only once. Also
called equivalent groups, posttest-only design

Question 19

pretest/posttest design

Answer 19

An experiment using 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 20

repeated-measures design

Answer 20

An experiment using 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 21

concurrent-measures design

Answer 21

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 22

order effect

Answer 22

In a within-groups design, a threat to internal validity in which
exposure to one condition changes participant responses to a later
condition. See also carryover effect, practice effect, testing threat

Question 23

practice effect

Answer 23

A type of order effect in which participants’ performance improves
over time because they become practiced at the dependent measure
(not because of the manipulation or treatment). Also called fatigue
effect. See also order effect, testing threat.

Question 24

carryover effect

Answer 24

A type of order effect, in which some form of contamination carries
over from one condition to the next

Question 25

counterbalancing

Answer 25

In a repeated-measures experiment, presenting the levels of the independent variable to participants in different sequences to control for order effects. See also full counterbalancing, partial counterbalancing.

Question 26

full counterbalancing

Answer 26

A method of counterbalancing in which all possible condition orders are represented. See also counterbalancing, partial counterbalancing.

Question 27

partial counterbalancing

Answer 27

A method of counterbalancing in which some, but not all, of the possible condition orders are represented. See also counterbalancing, full counterbalancing.

Question 28

latin square

Answer 28

A formal system of partial counterbalancing to ensure that every condition in a within-groups design appears in each position at least once.

Question 29

demand characteristic

Answer 29

A cue that leads participants to guess a study’s hypotheses or goals; a threat to internal validity. Also called experimental demand.

Question 30

manipulation check

Answer 30

In an experiment, an extra dependent variable researchers can include to determine how well a manipulation worked

Question 31

pilot study

Answer 31

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

Question 32

one-group, pretest/posttest design

Answer 32

An experiment in which a researcher recruits one group of participants; measures them on a pretest; exposes them to a treatment, intervention, or change; and then measures them on a posttest.

Question 33

maturation threat

Answer 33

A threat to internal validity that occurs when an observed change in an experimental group could have emerged more or less spontaneously over time.

Question 34

history threat

Answer 34

A threat to internal validity that occurs when an observed change in an experimental group could have emerged more or less spontaneously over time.

Question 35

regression threat

Answer 35

A threat to internal validity related to regression to the mean, a phenomenon in which any extreme finding is likely to be closer to its own typical, or mean, level the next time it is measured (with or without the experimental treatment or intervention). See also regression to the mean

Question 36

regression of the mean

Answer 36

A phenomenon in which an extreme finding is likely to be closer to its own typical, or mean, level the next time it is measured, because the same combination of chance factors that made the finding extreme are not present the second time. See also regression threat.

Question 37

attrition threat

Answer 37

In a pretest/posttest, repeated-measures, or quasi-experimental study, a threat to internal validity that occurs when a systematic type of participant drops out of the study before it ends

Question 38

testing threat

Answer 38

In a repeated-measures experiment or quasi-experiment, a kind of order effect in which scores change over time just because participants have taken the test more than once; includes practice effects.

Question 39

instrumentation threat

Answer 39

A threat to internal validity that occurs when a measuring instrument changes over time.

Question 40

selection-history threat

Answer 40

A threat to internal validity in which a historical or seasonal event systematically affects only the participants in the treatment group or only those in the comparison group not both

Question 41

selection attrition threat

Answer 41

A threat to internal validity in which participants are likely to drop out of either the treatment group or the comparison group, not both.

Question 42

observer bias

Answer 42

A bias that occurs when observer expectations influence the interpretation of participant behaviors or the outcome of the study

Question 43

demand characteristic

Answer 43

A cue that leads participants to guess a study’s hypotheses or goals; a threat to internal validity. Also called experimental demand.

Question 44

double-blind study

Answer 44

A study in which neither the participants nor the researchers who evaluate them know who is in the treatment group and who is in the comparison group.

Question 45

masked design

Answer 45

A study design in which the observers are unaware of the experimental conditions to which participants have been assigned. Also called blind design

Question 46

placebo effect

Answer 46

A response or effect that occurs when people receiving an experimental treatment experience a change only because they believe they are receiving a valid treatment

Question 47

double blind placebo control study

Answer 47

A study that uses a treatment group and a placebo group and in which neither the researchers nor the participants know who is in which group

Question 48

null effect

Answer 48

A finding that an independent variable did not make a difference in the dependent variable; there is no significant covariance between the two. Also called null result

Question 49

ceiling effect

Answer 49

An experimental design problem in which independent variable groups score almost the same on a dependent variable, such that all scores fall at the high end of their possible distribution. See also floor effect.

Question 50

floor effect

Answer 50

An experimental design problem in which independent variable groups score almost the same on a dependent variable, such that all scores fall at the low end of their possible distribution. See also ceiling effect.

Question 51

manipulation check

Answer 51

In an experiment, an extra dependent variable researchers can include to determine how well a manipulation worked

Question 52

noise

Answer 52

Unsystematic variability among the members of a group in an experiment, which might be caused by situation noise, individual differences, or measurement error. Also called error variance, unsystematic variance

Question 53

measurement error

Answer 53

The degree to which the recorded measure for a participant on some variable differs from the true value of the variable for that participant. Measurement errors may be random, such that scores that are too high and too low cancel each other out; or they may be systematic, such that most scores are biased too high or too low.

Question 54

situation noise

Answer 54

Unrelated events or distractions in the external environment that create unsystematic variability within groups in an experiment

Question 55

power

Answer 55

The likelihood that a study will show a statistically significant result when an independent variable truly has an effect in the population; the probability of not making a Type II error