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Unformatted text preview: g to say that yes that relationship exists and there is no
other explanation. Its trying to control for all those extraneous
variables. You have to put it in a controlled environment or lab
environment. You lose any ability to translate it to the natural
External validity: Doing the research in a field, you have to −Field experiments
• Tradeoffs Laboratory Versus Field Experiments
Factor Laboratory Field Environment Artificial Realistic Control High Low Reactive error High Low Demand artifacts High Low Internal validity High Low External validity Low High Time Short Long Number of units Small Large Ease of implementation High Low Cost Low she didnt talk about this High Types of Extraneous Factors
• Selection Bias
• Instrument Variation
• Testing Effects
• Regression Toward the Mean What we are trying to control for. Selection bias: making good
choices on who the participants of the experiment will be.
Instrument variation: have to make sure there is no concerns
over consistency between the two testing groups (or whatever it
might be) this is when the experiment isnt administered in the
same way. History: from the start of the experiment to the end,
there could be variables that come in through the length of the...
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This document was uploaded on 03/25/2014.
- Spring '14