Please enable JavaScript.
Coggle requires JavaScript to display documents.
Sampling Methods and Experimental Designs (1.2) - Coggle Diagram
Sampling Methods and Experimental Designs (1.2)
Key Ideas
Population:
The group of people about which we wish to draw conclusions
Sample:
The members of the population who have been chosen to take part in the research
Experimental group:
the group of research participants 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:
the group of research participants 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
Random allocation:
a subject-selection procedure where all participants who have been selected for an experiment have an equal chance of being in the E-group or C-group
Placebo effect:
refers to the participants' behaviour being influenced by their expectations of how they should behave, caused by the belief that they have received some treatment
Single-blind procedure:
Allocating participants to group in such a way that they do not know whether they are in the E-group of the C-group
Experimenter effect:
The outcome of an experiment being influenced by the person conducting the experiment
Double-blind procedure:
The method of allocating participants to groups so that neither the experimenter nor the participants are aware of who is in the E-group or C-group
Sampling
Convenience sampling:
Using whoever is available at the time of research
Random sampling:
A sampling procedure in which every member of the population has an equal chance of being selected
Stratified sampling:
A sampling process by which the effects of a certain variable can be eliminated as a possible confound in an experiment
Identifying a property that we believe may interfere with the effects of the IV on the value of the DV.
Measuring that property for each member of the population.
Dividing the population into particular strata (groups) based on the value of that variable.
Deciding on the number of participants required for the experiment.
Selecting participants int he same proportions as exist in the population to make up the sample (a stratified sample).
Selecting a random sample from each stratum, in the same proportions as exist in the population (a stratified random sample).
Experimental Designs
Repeated measures design:
A subject-selection procedure where each participant is part of both the E-group and the C-group
Counterbalancing:
A method for controlling order effects in a repeated measures design
Matched participants design:
A subject-selection procedure that attempts to eliminate confounding variables by 'matching', on key characteristics, each individual in the experimental group with an individual in the control group
Independent groups design:
Allocates participants to E-group or C-group at random; also known as 'between participants design'
Developmental research designs
Longitudinal study:
A form of repeated measures design where the same participants are investigated over a period of time
Cross-sectional design:
A form of independent groups design, where data is collected at one time from participants of all ages and different age groups, and compared
Sequential designs:
A combination of longitudinal and cross-sectional designs, which draws on strengths and eliminates weaknesses of either approach