PSY 101 Chapter Notes - Chapter 2-2: Inverse Relation, Naturalistic Observation, Ethology
KEY
people--BLUE
works/ideas/beliefs/theories--ORANGE
importance--YELLOW
Correlation and Prediction
• Strong correlation gives scientists the ability to make a strong prediction based on their findings
• As strength of correlation increases, predictability of other variable increases
• Correlation of Determination
o (Correlation Coefficient)2
o Percentage of variation in one variable that can be predicted based on the other variable
o Example
▪ Correlation of .30 would not yield much predictive power
▪ Correlation of .90 would allow very accurate predictions
• Positive and Negative Correlation
o Correlation Coefficient
▪ Numerical index of the degree of relationship between two variables
▪ Can be positive or negative
▪ Ranges from -1 to 1
o Positive Correlation
▪ Two variables co-vary in the same direction
• High X --> High Y
• Low X --> Low Y
o Negative Correlation
▪ Inverse relationship between two variables
• High X --> Low Y
• Low X--> High Y
Correlation and Causation
• Correlation between X and Y does not explain how one causes the other
o Does X cause Y?
o Does Y cause X?
o Are both caused by Z (a third variable)?
• Correlation ≠ Causation
Independent and Dependent Variables
• Experiment
o Method in which the investigator manipulates a variable under carefully controlled
conditions and observes whether any changes occur in a second variable as a result
o Purpose
▪ How X affects Y
▪ X independent variable
▪ Y dependent variable
• Independent Variable
o Condition or event that an experimenter changes
• Dependent Variable
o Variable through to be affects by the manipulation of the independent variable
Experimental and Control Groups
• Experiment Process
Document Summary
Low x --> low y: negative correlation. Inverse relationship between two variables: high x --> low y. Correlation and causation: correlation between x and y does not explain how one causes the other, does x cause y, does y cause x, are both caused by z (a third variable), correlation causation. Independent variable: condition or event that an experimenter changes, dependent variable, variable through to be affects by the manipulation of the independent variable. In-depth study of a phenomenon in its natural setting: eibl-eibesfeldt, ethologist, person who watches behavior for a living in both people and animals. Key people--blue works/ideas/beliefs/theories--orange importance--yellow: drawbacks: no ability to follow up on questions, occasional dishonesty, to predict things, correlation and causation, correlation coefficient. Statistic that tells us how strong a relationship is: ranges from -1 to +1. 99 and -. 99 are exactly the same strength in correlation. Stronger conclusions than correlations about causes: experiments are rerun multiple times under multiple conditions.
