research methods and experimental design

Question 1

extraneous variables

Answer 1

all variables apart from the independent variable which could affect the results of an experiment e.g. temp of the room

Question 2

confounding variables

Answer 2

act as an additional independent variable - affects the result of an experiment e.g. age, gender

Question 3

demand characteristics

Answer 3

bias possibly formed from cues inadvertently provided that suggest to the participants what the outcomes of the investigation may be

Question 4

participant reactivity

Answer 4

when the participant tries to please the expectations

Question 5

investigator effects

Answer 5

unwanted influences that the investigator/experimenter communicates to the participants which affects their behaviour and so biases the results

Question 6

chi^2 test

Answer 6

used when your data is in categories - to see if the data is related

Question 7

what are independent groups or pairs?

Answer 7

subjects allocated to different groups with different experimental conditions

Question 8

matched pairs

Answer 8

subjects are matched for at least one variable that could affect the outcomes of the experiment e.g. age, gender

Question 9

repeated measures

Answer 9

all subjects experience both experimental conditions

Question 10

counterbalancing

Answer 10

all subjects experience both experimental conditions but in different orders - stops the order of the tasks affecting the outcome

Question 11

random allocation

Answer 11

subjects once matched are then randomly assigned to the different experimental conditions

Question 12

nominal data

Answer 12

used to label variables without providing a quantitative value e.g. genotype, gender

Question 13

ordinal data

Answer 13

classified into categories within a variable to have a natural rank order

Question 14

sign test

Answer 14

used to measure difference between results

Question 15

directional hypothesis

Answer 15

a prediction made by a researcher regarding a positive or negative change, relationship or difference between two variables of a population

Question 16

Analysis for significance

Answer 16

• spearmans correlation (non-parametric)
• pearson’s rho correlation (parametric)
• both pearsons and spearmans test the strength of association between two continuous variables and both can be used with quantitative data

Question 17

choose pearsons if…

Answer 17

• data is linear
• change between the variables is proportional
• have numeric data
• can only use raw data

Question 18

choose spearmans if…

Answer 18

• data is monotonic (may have curvy bits)
• change between variables may not be proportional
• have numeric or ordinal data
• data will be ranked

Question 19

data for non-parametric tests

Answer 19

• nominal or ordinal
• not normally distributed
• outliers/ anomalies
• unequal variances
• small samples

Question 20

interval level data

Answer 20

data measured in fixed units equal distance between points on the scale

Question 21

normal distribution

Answer 21

data distributed evenly around the mean

Question 22

skewed distribution

Answer 22

data does not look normal