Experiments

Question 1

IV.

Answer 1

The variable that the experimenter manipulates. The changes are called ‘conditions’.

Question 2

DV.

Answer 2

The variable that is measured. It will change depending on what the experimenter does to the IV.

Question 3

Manipulation of variables and measurement of the resultant…

Answer 3

…change helps to establish a ‘cause and effect’ relationship between 2 or more events.

Question 4

Hypotheses.

Answer 4

All experiments are testing a hypothesis. This is a statement that specifies what is going to be tested and how it will be measured.

Question 5

Experimental hypothesis.

Answer 5

Predicts the effect of the IV on the DV. E.g there will be a difference between…

Question 6

In order for the hypothesis to be tested it needs…

Answer 6

…to be ‘operationalised’ (made testable).

Question 7

The Null Hypothesis.

Answer 7

States that there will be no effect of the IV on the DV. E.g, there will be no difference between…

Question 8

One tailed hypothesis.

Answer 8

Predicts the direction in which results are expected to occur.

Question 9

Two tailed hypothesis.

Answer 9

Will simply state that there is some kind of difference between the two events.

Question 10

Reliability in experiments.

Answer 10

Refers to whether a measurement device is consistent. A measurement is said to be reliable if the measurement can produce similar results of used again in similar circumstances.

Question 11

Internal reliability.

Answer 11

Refers to whether the procedure is the same within the experiment. E.g, for every participant or between conditions.

Question 12

External reliability.

Answer 12

Refers to whether the procedure is the same between experimenters. E.g, when the study is replicated at a later date will it give the same/similar results assuming nothing has changed.

Question 13

Validity.

Answer 13

Refers to whether an experiment really measure what it claims to.

Question 14

Internal validity.

Answer 14

Refers to whether a test measures what it claims to measure.

Question 15

Test validity.

Answer 15

Refers to whether a test measures the effect of the IV on the DV.

Question 16

Extraneous variable.

Answer 16

Factors other than the IV that could cause the DV to change. E.g, light, noise, temperature, etc.

Question 17

The experimenter needs to attempt to control these…

Answer 17

…EV’s so he/she knows they have not caused the changes in the DV.

Question 18

(Experimental design)

Repeated measures.

Answer 18

Compares the performance of participants in one condition with their own performance in another condition.

Question 19

Repeated measures.

+

Answer 19

Individual differences of participants are removed since each participant is compared against him/herself.

Question 20

Repeated measures.

-

Answer 20

People may do better or worse on the second condition, e.g, they may become bored.

Question 21

Repeated measures.

–

Answer 21

Participants may be able to guess the aims of the study, which may cause demand characteristics.

Question 22

Independent measures.

Answer 22

Compares the performance of different participants in each of the experimental conditions.

Question 23

Independent measures.

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Answer 23

Participants are less likely to guess the aims of the study.

Question 24

Independent measures.

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Answer 24

Differences in performance between 2 groups may be due to individual differences (you may be measuring that rather than the effects of IV) (validity).

Question 25

All experiments…

Answer 25

…involve the manipulation of an IV to see its effects on the DV.