Preventing error and bias

Question 1

what is an extraneous variable

Answer 1

any variable that is not the iv butt may cause an unwanted effect on the dv, they are identified at the start of the experiment

Question 2

what is a cofounding variable

Answer 2

a variable other than the iv that has systematically affected the dv, can only be identified after the study

Question 3

examples of cofounding and extraneous variables

Answer 3

participant related variables, order effects, placebo effects, experimenter effects, situational variables, non-standardised instructions and procedures and demand characteristics

Question 4

participant related variables

Answer 4

the characteristics of a study’s participants that may affect the results

Question 5

how to reduce participant related variables

Answer 5

large sample size and using random or stratified sampling rather than convenience and using a withiin subject design

Question 6

order effects

Answer 6

the tendency for the order in which participants complete experimental conditions to have an effect on their behavior

Question 7

examples of order effects

Answer 7

practice effects, fatigue effects and expectations

Question 8

how to reduce order effects

Answer 8

counterbalancing

Question 9

what is counterbalancing

Answer 9

it involves the systematic manipulation of the presentation of tthe different levels of the iv, e.g one group does a-b, the other doe sb-a

Question 10

what is the placebo effect

Answer 10

a type of expectancy effect, where a participants expectations about the treatment/condition cause changes in their behavior

Question 11

the two ways a placebo is used to control the placebo effect

Answer 11

1. helps to equalise the expectancy across both groups, none of the study know what treatment they are getting 2. partcipants would be told that there is a placebo being used and they may/ mey not recieve it

Question 12

what is a placebo

Answer 12

an inactive substance or treatment, the control group

Question 13

do placebos stop the placebo effect

Answer 13

not necesarily, they help researchers understand how significantly an active intervention may affect individuals

Question 14

demand characteristics

Answer 14

cues in an experiment that may signal to a participant the intention of the study and influence their behaviour, they are more likely to conform to the studys hypothesis and meet the studys ‘demands’

Question 15

experimenter effects

Answer 15

the expectations of the researcher affects the results of an experiment

Question 16

how to reduce experimenter effects

Answer 16

double blind procedures

Question 17

single blind procedures

Answer 17

a procedure where participants are unaware of the experimental group or condition they have been allocated to

Question 18

single blind procedures reduce…

Answer 18

participants expectations and can reduce the placebo effect

Question 19

double blind procedure

Answer 19

a procedure where both participants and experimenter do not know which conditions or groups the participants are allocated to

Question 20

what does double blind procedures reduce

Answer 20

prevent the experimenter effects, demand characteristics and experimenter and participant expectations

Question 21

situational variables

Answer 21

any environmental factor that may affect the dependent variable, they can be extraneous and/or cofounding variables

Question 22

examples of situational variables

Answer 22

temperature, lighting, weather, time of day, noise location

Question 23

non-standardised instructions and procedures

Answer 23

occur when the directions and procedures differ across participants or experimental conditions. this introduces unwanted situational variables for either participants or entire experimenter geoups

Question 24

how to reduce situational variables

Answer 24

standardised testing, conditions and procedures

Question 25

what are standardised testing, conditions and procedures

Answer 25

ensuring that each participant in an experiment recieves the same instructions and follows the same procedures in each condition, sometimes the info about the true purpose of study is withheld or decieved

Question 26

standardised testing, conditions and procedures reducee

Answer 26

extraneous variables of non-standardised instructions and procedures and allows researchers to conclusively infer that the results are due to the IV

Question 27

controlled variables

Answer 27

variables that remain constant so that their iimpact is systematically minimised and accounted for