Experimental Method and Quasi Experiments Flashcards
What is an experimental method?
- trying to establish cause and effect
- looking at a link between the IV and DV
What are the key features of the experimental method?
- manipulating the IV
- controlling extraneous variables
- measuring dependent variables
What is the IV?
- what the experimenter systematically varies/manipulates
- normally need at least 2 levels
- sometimes can’t manipulate directly so manipulate theoretical variables indirectly and then check IV was done successfully
What is the DV?
- the result/outcome
- variable that’s measured
What are the different types of independent variables?
- situational variables
- task variables
- instructional variables
What is control group/condition?
-where there’s an absence of manipulation
What is experimental group/condition?
-where manipulation is administered
What is an extraneous variable?
- any variable that isn’t of immediate interest to a researcher but may pose a threat to validity as it compromises interpretation
- usually obscures the measurement of processes of interest
What is a confounding variable?
- unintended or accidental manipulation of an extraneous variable that occurs because the variable is associated with an independent variable in an experiment
- systematic effect of extraneous variable may be mistaken for effect of IV
What is a confounding result?
-situation where extraneous variables co-varies with the IV and provide alternative interpretation of the results
What is systematic effect?
-affects one of the conditions more than it affects the control condition
How to decide on how to measure dependent variables?
- could refer to previous research
- run a pilot study
What is a pilot study?
- small number of participants
- can identify phenomena that may interfere with ability to detect cause and effect
Definition of ceiling effect?
- task is too easy
- scores are all very high so differences between participants will be disguised
Definition of floor effect?
- task is too difficult
- scores are all very low so the differences between the participants will be disguised
What is a relevance-sensitivity trade off?
-the more sensitive a DV is to changes made in the IV the less relevant it may become to real-world phenomena
What conclusions can be made from experimental studies?
- extraneous variables can be controlled for
- casual inference can be made
- can conclude that changes in the IV cause changes in the DV
What conclusions can be made from quasi-experimental studies?
- extraneous variables can’t be controlled
- casual inference can’t be established
- can’t say IV is cause of DV
- can say groups performed differently on the DV
What are quasi-experimental variables?
- where differences between IVs already exist without manipulation from the researcher
- can’‘t be manipulated really
Examples of quasi-experimental variables?
- gender
- age
- cultural group
- intelligence
- personality traits
Definition of spurious associations?
-have no direct relationship between one variable and the other
