PS101 Lecture Notes - Lecture 5: Myelin, Null Hypothesis
Document Summary
Correlation: if cause and effect does exist, correlation exists, def"m: measures and determines the relation between two variables, (co-relation - reaction of two things, eg. number of friends and self-esteem. Correlation compared to descriptive methods: more rigorous in terms of control, empirical measurements and statistical analysis, still no causation. Kinds of correlations: positive: as one variable goes up, the other does two (ie. study time and grades) - (positive slope) Ie. happiness and helpfulness, income and education (just related no. Causation: about causation: seems sensible that study time predicts performance, these things co-occur but don"t necessarily cause each other. Could be another variable (like what you do in free time: negative: as one variable goes up, the other goes down. Strength of a correlation: number: higher the number, stronger the correlation, the positive or negative sign re ects direction not strength, 0-1= positive and -1-0= negative, strongest is the number that is closest to 1.
