Health Sciences 2801A/B Lecture Notes - Lecture 3: Scatter Plot, Categorical Variable, Negative Relationship

• School: Western University
• Department: Health Sciences
• Course: Health Sciences 2801A/B
• Professor: Christopher Lee

Document Summary

Scatter plot visual representation of relationship between two variables: positive relationship increase in both variables, negative relationship increase in one variable, decrease in the other, you know what this looks like. Straight line is fit to the relationship between two variables: y= a + bx, independent variable (x) can be continuous variable or categorical variable. Continuous variable - involves in differences in amounts: dependent variable is always a continuous variable, ex. Different levels of blood pressure: such as two kinds of tea. Categorical variable involves differences in classification. Slope of regression can have direct effect or indirect effect of. Observed score predicted score independent variable on dependent variable. Example of direct effect is predicting calories on basis of fat: represents direct effect because additional fat always results in additional calories, one gram of fat produces approximately 9 calories. Example of indirect effect when there is reason to believe that another variable mediates the relationship between the i. v and d. v: ex.