Measuring and Manipulating Variables

Question 1

variables

Answer 1

“environmental” factors that can have at least two levels

Question 2

what are 4 types of independent variables?

Answer 2

physiological
experience
stimulus/environmental
participant/subject

Question 3

physiological

Answer 3

IV: manipulation of a participant’s normal biological state

Question 4

experience

Answer 4

IV: manipulation in the amount or type of training or learning that has long term effects on the person

Question 5

stimulus/environmental

Answer 5

IV: manipulation of some aspect of the environment, short term change that lasts only as long as the study

Question 6

participant/subject

Answer 6

IV: aspects of the participant treated as if they are IV’s

Question 7

to select your dependent variable, consider:

Answer 7

1. should relate back to your hypothesis
2. be operationally definable
3. be both valid (relates to measure of interest) and reliable (consistent measurement)

Question 8

what are 4 types of dependent variables?

Answer 8

correctness
rate/frequency
degree/amount
latency/duration

Question 9

correctness

Answer 9

DV: how many were right?

Question 10

rate/frequency

Answer 10

DV: how often did it occur within a certain time interval

Question 11

degree/amount

Answer 11

DV: how much of it was there?

Question 12

latency/duration

Answer 12

DV: how fast? how long did it last?

Question 13

types of extraneous variables:

Answer 13

nuisance variables

Question 14

nuisance variables

Answer 14

unwanted variables that vary randomly across participants and increases the variability of scores within groups. affects all groups (thus not a confound).
allows us to generalize our results, harder to determine effect but conclusion will still be valid.

Question 15

confounding variables

Answer 15

unintended variables that create a systematic difference between the groups on the DV, renders results meaningless

Question 16

what can one do to ‘control’ against extraneous variables?

Answer 16

randomization, elimination, constancy, balancing

Question 17

randomization

Answer 17

equal chance of being assigned to any group in the experiment, makes sure there are no pre-existing differences between groups, needs a large sample size, removes confounds but has no effect on nuisance variables

Question 18

elimination

Answer 18

specific extraneous variables completely removed from the experiment.
-you must know what the potential extraneous variables are, not always easy in practice (ex. time)

Question 19

constancy

Answer 19

when it is impossible to completely remove an extraneous variable, a researcher may try to minimize its effects by having it remain constant for all participants
-often refers to testing conditions

Question 20

balancing

Answer 20

when it is impossible to completely remove an extraneous variable, a researcher may try to minimize its effects by distributing it to all groups equally
-basically, all EXPERIMENTERS test all CONDITIONS equally

Question 21

what are two effects that may result from balancing?

Answer 21

(sequence of order effects and carry-over effects may result)

Question 22

order effects

Answer 22

when position in a series affects how participants respond, doesn’t depend on the event but the position

Question 23

carryover effects

Answer 23

when the effects of one event influence responses to the next event, specifically depends on the event previous (not position)

Question 24

how can one reduce the ‘side effects’ of balancing?

Answer 24

counter-balancing (varying the order in which items are present)
-i.e. within-subject/within-group and complete/incomplete

Question 25

within-subject

Answer 25

every subject tests all orders and conditions

ex. (AB) and (BA)

Question 26

within-group

Answer 26

each participant tests one order

ex. (AB) or (BA)

Question 27

complete

Answer 27

all conditions are tested in one subject (A and B both tested)

Question 28

incomplete

Answer 28

random testing of a single portion of the condition (A or B tested)

Question 29

what are the requisites for complete counterbalancing?

Answer 29

each event must be presented an equal number of times to other events, and be tested in a position/order of a sequence an equal number of times and precede some other event an equal number of times