PSY 311 Lecture Notes - Lecture 3: Dependent And Independent Variables, Stressor, Attention Span
Document Summary
Correlation coefficient: strength and direction of relationship between variables, ranges between -1 and 1. Positive example: as studying time increases, grades increase. Negative example: as exercise increases, waistline decreases. No correlation: the more letters in someone"s name the better looking they are. Reasons smoking causes lower gpa: time spent smoking could be spent in classroom or studying, attention span, cost of cigarettes, oxygen level in blood decreases when smoking. Reasons lower gpa causes smoking: grades stress you out causing you to smoke more. Possible third variable: low ses, stressor (death in family) Example: as ice cream sales go up, homicide rates go up. A = homicide: happy after killing someone you celebrate with ice cream. B = ice cream: hyped up on sugar then go kill someone. C = heat: causes aggression (homicide) and need to cool down (ice cream, experimental. If dependent variable changes due to independent we can conclude causation.
