Chapter 4 Research methods
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Chapter 4 Research methods
What is a variable
Anything we measure, or can change, be held constant etc. It is an event situation, behavior, or individual characteristic that varies.
How many levels should a variable have?
What kind of values may a variable have?
Numeric or qualitative
What is a operational definition for a variable?
A set of procedures to measure or manipulate it
-it helps with communicating meaning to others
-Requires definition in concrete terms
What is construct validity
Am I measuring what I say I'm measuring? Does operational definition reflect meaning of variable?
What is a positive linear relationship
Increases in one variable are accompanied by increases in another variable (diagonal line going up)
Negative linear relationship
Increases in one relationship and decreases in another
Increases in one variable are accompanied by systematic increases and decreases in another variable
-direction of relationship changes
-May be U-shaped or inverted U-shaped.
No association between variables (flat line)
What is a correlation coeficient
The number between 0-1 that accompanies the negative or positive symbol.
What does a correlation coefficient do?
-Indicates how strongly variables are related (closer to one, stronger relationship is)
-Allows prediction of changes in one variable from changes in another
-Helps explain random variability
Relationships are studied by making observations or measures of the variable of interest.
What are some nonexperimental methods?
-Self-report descriptions of behavior
-examining public records
-variables observed as if they occurred naturally and relationship established if vary together.
What constitutes a non-experimental method?
-No variable is manipulated-all measured
What are some problems with non-experimental methods?
-Not good when trying to determine cause and effect
-difficult to determine direction of relationship
Experimenter manipulates a variable and observes the effect on a second variable
What do you do with the variables in an experimental method?
Manipulate one, measure the other-allows for determination of direction of cause and effect
What does the experimental method attempt to do?
Control potential extraneous variables or confounding variables
In an experimental method, everything is held constant except for what?
What kind of procedures are used in experimental method?
What is experimental control?
All extraneous variables are held constant
-treat all participants from all groups identically, except for manipulated variable.
What does experimental control eliminate
What does randomization do?
Ensures that an extraneous variable is just as likely to affect one experimental group as it is the other groups in the experiment
for between subjects design (each participant participates in one thing)-randomly assign to groups (random number draw).
within subject design (everybody goes through each condition) but the condition order is randomized for each person with a break inbetween.