correlations ap psychology. correlations co-relation it describes the relationship b/w two...
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CorrelationsAP Psychology
Correlations
Co-relation It describes the relationship b/w two variables.
Example #1 How is studying related to grades? # of hours a student studies for an exam scores on the examsFind: as their hours of study increased, their grades
increased.
Positive correlations
• Indicates a direct relationship between variables.
• An increased in one variable is accompanied by an increase in another variable or a decrease in one variable is accompanied by a decrease in another variable.
Example #2
• How is television viewing related to grades? ask an individual to calculate the average
# of hours a day he or she watches. Grades could be measured by the grade
point average obtained at the end of the school year.
May find: amount of TV. increased, GPA decreased.
Negative Correlation
• Indicates an inverse relationship b/w variables; an increase in one variable is accompanied by a decrease in another variable.
Think of correlations this way
• correlation is a lot like a relationship between a couple:
• If you have a positive relationship you both are headed in the same direction.
• If you have a negative relationship you go your separate ways.
How are correlations measured?
Correlation Coefficients.• Correlations are measured with #’s ranging from
-1.0 to +1.0• +1.0 and -1.0 are Perfect Correlations• 0 indicates no correlation b/w variables.As the # increases toward +1.0, the coefficient
shows an increasing positive correlation.As the # moves closer to -1.0, the stronger the
neg. correlation b/w variables.
Continue from previous slide
• Examples:• +.79 and -.79 are both strong correlations• -.22 is a weak correlation• Remember that the (+) and (-) indicate the
direction of the relationship.
Causation?
• CORRELATION DOES NOT IMPLY CAUSATION.• Correlation research is a process that indicates
the probability that when one variable exists, the other variable will also be present or affected.
Scatter Plots/Grams
• Can give a visual representation of correlations.
More Scatter Plots examples
Scatter plots
Scatter plot examples
Scatter plot example
What is an IV and a DV in a correlational study.
• Though a researcher is not directly manipulating a situation (such as in an experiment), he/she is manipulating the data (choosing what to look at).
• I am doing a correlational study trying to find a correlation between height and income.
• My IV is height (since I have chosen or grouped people by height, it is what I chose to manipulate), my DV is income.
• I do a correlational study looking for a relationship between grade level and test scores.
• My IV is grade level, my DV is test score.