AOS 1 CHAPTER 1 Flashcards
(21 cards)
Independent Variable
the variable that is manipulated by the experimenter who then measures resulting changes in the dependent variable
Dependent variable
the property which is measured in psychological research, to look for effects of the independent variable
Extraneous variable
a variable other than the independent variable that could cause changes in the value of the dependent variable
Hypothesis
a prediction of the outcome of research, stated in terms of the influence of changes in the value of the independent variable on the value of the dependent variable
Sample
the members of the population that have been chosen to take part in the research
Stratified sampling
Dividing population into categories and selecting at random in proportions equivalent to population
Random sampling
a sampling procedure in which every member of the population has an equal chance of being selected ALSO MEMORISE PROS AND CONS P9
Mean
the average of all the scores, calculated by adding up all the scores and dividing that total by the number of scores
Median
the score that occurs exactly halfway between the lowest and the highest score
Mode
the most commonly occurring score in the dataset
Range
the difference between the highest score and the lowest score in the dataset
Steps of scientific method
1 Identify the area of research and form a research aim
2 Collect information
3 Identify the research question and formulate a hypothesis
4 Design a research method to test the hypothesis
5 Collect and analyse the data
6 Draw a conclusion
7 Report findings
8 Test the conclusion
Population
In research, we are always interested in drawing conclusions that are valid for a particular group or groups of people. The group about which we wish to draw conclusions is referred to as the population.
Experimental group (E-Group)
the group of research participants which is exposed to the independent variable. The results are compared with the control group so that the effects of the independent variable can be determined.
Control Group (C-Group)
the group of research participants which is not exposed to variations
in the independent variable. The results are compared with the experimental group so that the effects of the independent variable can be determined.
3 experimental designs used to control extraneous variables
Repeated measures
Matched participants
Independent group
Repeated measures
a subject selection procedure where each participant is part of both the E-group and C-group. Also known as ʻwithin participants design’. This increases reliability as the same person is being used making the differences in tests more reliable but it is time consuming to repeat the test with the same person.
Matched participants
In the matched participants design a researcher identi es a variable that is a likely confound, and eliminates the e ects of this variable from the experiment. Participants can be ranked in accordance with their scores on this variable and then allocated to the respective groups. Example, measuring effect on IQ, each group should have the same mean iq scores, this is time consuming but the variable being matched (IQ) will not have an extraneous effect on the DV.
Independent group
The independent groups design (also known as between participants design) allocates participants to the E-group or the C-group at random.
This design is used when undertaking cross-sectional studies – drawing conclusions about a population in one moment of time.
> Advantage: The independent groups procedure can all be done at once and drop-
outs are unlikely.
> Disadvantage: The procedure needs a large number of participants to ensure that
the spread of participant variables in the sample will match the spread in the population.
Controlled Variable
This is any factor which must be held constant to allow the experiment/research to take place. E.g. In an experiment on memory, using the same world list in the test for all participants.
Confounding variable
This is any factor besides the independent variable which influences the dependent variable. This means that it is not possible to determine which factor caused a change in the dependent variable.
