experiments and data

Question 1

what is an experiment

Answer 1

an experiment is when the researcher deliberately changes one thing in order to find out if it has an effect on another thing

Question 2

why are experiments different and important

Answer 2

they tell you wether one variable has a causal influence on another variable

Question 3

what is an independent variable (IV)

Answer 3

variable that is manipulated as we think it links to the DV

Question 4

what is a dependant variable (DV)

Answer 4

variable that is measured

Question 5

what can we conclude from the IV and DV

Answer 5

-if IV is manipulated and there is no change to the DV, there can be no causal relationship between the 2

-if the DV changes when IV is manipulated, this suggests that changes in the DV was caused by changes in the IV

Question 6

what is operationalisation

Answer 6

Explaining precisely how IV can be manipulated and how DV can be measured.

Question 7

Why is operationalisation important?

Answer 7

-enables replicability
-removes subjectivity and bias increasing the reliability

Question 8

what is a confounding variable

Answer 8

any uncontrolled variable that affects the conditions differently eg being certain that changing the IV was the only different between the conditions not another variable

Question 9

what are 2 possible problems with the existence of a cofounding variable

Answer 9

1-any difference you find in the DV between the conditions might have been caused by the uncontrolled variable so you might conclude that the IV has affected the DV when it hasn’t

2-uncontrolled variable may cancel out the effect of the IV so you end up concluding that the IV had no effect on the DV when it actually did

Question 10

what are the three different types of experiments

Answer 10

independent groups, matched pairs and repeated measures

Question 11

explain how independent groups work

Answer 11

1-recruit a sample

2-divide them into 2 groups randomly

3-each pp is then exposed to only one condition

4-the DV is measured and the averages are compared

Question 12

what are some strengths of the independent groups design?

Answer 12

1-it’s easier to keep the conditions the same meaning it’s also easier to control confounds

2-pp are less likely to guess the aim as they only take part in one condition, they don’t know about the other condition so demand characteristics are reduced

Question 13

what are some weaknesses of the independent groups design?

Answer 13

1-groups will somewhat differ from each other as your using different participants for each condition

2-have to recruit twice as many pp

3-individual difference will mean that there will be variables between the pp so c=any comparisons made between the 2 groups are unreliable

Question 14

describe the repeated measures design

Answer 14

1-recruit a sample

2-both groups are exposed to both conditions

Question 15

what are some strengths of the repeated measures design

Answer 15

-fewer pp are needed as they are used twice so it is more economical than the independent group design

Question 16

what are some weaknesses of the repeated measure design

Answer 16

1-chance of pp displaying demand characteristics as they have knowledge of all the conditions and so more likely to guess the aim

2-practice/order effect; performance from one condition is influenced by the previous condition eg practice and fatigue which introduces new confounds

Question 17

how can we fix the problems from a repeated measures design

Answer 17

1-using diff materials for each condition to remove the effect of practice however they all need to be equivalent or it introduces a new confound

2-reduce demand characteristics by using a single blind technique

3-control order effects by using randomisation or counterbalancing to ensure pp experience the conditions in diff orders

Question 18

what is randomisation

Answer 18

selecting randomly which condition the pp does first

Question 19

what is counterbalancing

Answer 19

An attempt to control for the effects of order in a repeated measures design: half the participants experience the conditions in one order, and the other half in the opposite order. so AB then BA

Question 20

describe how the matched pairs design works

Answer 20

1)recruit a sample

2)look at them individually and recruit a matched sample to each pp

3)randomly assign them so person 1 from the pair does condition one first and person 2 does condition 2 first

Question 21

what are some strengths of the matched pairs design

Answer 21

ensures that conditions can be compared reliably and that any difference found between the results of each condition is likely due to the DV and not individual differences allowing causation to be established

Question 22

what are some weaknesses of the matched pairs design

Answer 22

1)time consuming to recruit 2 well matched samples

2)difficult to match pp on all possible characteristics that could effect the DV

3)small sample as if one drops out you actually lose 2 pps

Question 23

why is a matched pairs design better than both ID and RM

Answer 23

-reduces demand characteristics

-reduces any individual differences

-reduces the effect of practice and order

Question 24

what are some strengths of correlational studies over experiments

Answer 24

-often occur in a natural setting without manipulating variables so more reflective of real life behaviour

Question 25

what are some strengths of experiments over correlational studies

Answer 25

1-correlational studies are unable to draw conclusions about causality as even if 2 variables are strongly related, it is unclear wether one causes another or if a 3rd variable is responsible for the behaviour whereas in an experiment only one thing could be causing this which is a change in the DV 2-correlational studies are more susceptible to confounding variables

Question 26

what is a directional hypothesis in an experiment

Answer 26

PP who do condition 1 will DV higher/more than PP who do condition 2

Question 27

what is a null hypothesis in an experiment

Answer 27

there will be no difference in DV between condition 1 and condition 2

Question 28

what is a non directional hypothesis in an experiment

Answer 28

there will be a difference in DV between condition 1 and condition 2

Question 29

what is a manipulation check

Answer 29

ensures that the independent variable is actually influencing the dependent variable -done before changing the IV eg asking pp questions to see if they understood what they have to do