Types of experiments & sampling Flashcards
What is a laboratory experiment?
- An experiment that takes place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV
Strengths of a laboratory experiment
-high control over confounding and extraneous variables
-can establish cause & effect (high internal validity)
- easy to replicate because of high level of control
Weaknesses of a laboratory experiment
-high chance of demand characteristics
- lacks mundane realism (not like everyday experience)
-lacks generalisability (lab is artificial)
-low external validity
What is a field experiment?
- An experiment that takes place in a natural setting within which the researcher manipulates the IV and records effect on the DV
Strengths of a field experiment
- less chance of demand characteristics
-higher mundane realism - high external validity (produces more valid and authentic behaviour)
Weaknesses of field experiments
- cause and effect difficult to establish due to loss of control of EVs and CVs (low internal validity)
-precise replication impossible
-ethical issues if participants are unaware they are being studied (cannot consent)
What is a natural experiment?
- An experiment where the change in IV is not brought about by the researcher
- The IV is naturally occurring and researcher records effect on the DV
Strenghts of a natural experiment
- provides opportunities for research that may not otherwise be undertaken for ethical or practical reasons
- high external validity (study of real world issues)
- less chance of demand characteristics
Weaknesses of a natural experiment
- naturally occurring events may happen rarely reducing opportunities for research
- low control over the EVs and CVs, cause & effect hard to establish - low internal validity
- cannot be replicated
What is a quasi experiment?
An experiment in which the IV is naturally occurring but is based on an existing difference between people (age, gender)
Strengths of a Quasi experiment
- high ecological/external validity- due to lack of involvement of researcher
> findings can be generalized to real-life settings
Weakenesse of quasi experiment
- low internal validity - researcher cannot accurately assess affect on DV due to lack of control of EVs and DVs
- not replicable- due to researchers lack of control so reliability cannot be assessed
What is meant by term population?
- A large group of individuals that a researcher is interested in studying
What is meant by the term sampling sample?
- A smaller group of individuals drawn from a target population and are representative of that population
What is meant by the term sampling sample?
- A smaller group of individuals drawn from a target population and are representative of that population