PS296 Chapter Notes - Chapter 9: Scatter Plot
Chapter 9: Correlation
-when we are dealing with the relationship between two variables, we are concerned with
correlation, and our measure of the degree or strength of this relationship is represented by a
correlation coeeficient
Scatter Diagrams:
-every experimental subject or unit or observation in the study is represented by a point in
two dimensional space
-the coordinates of this point (Xi, Yi) are the individual's scores on variables X and Y
-predictor variable/independent variable is traditionally presented on the X axis
-criterion variable/dependent variable traditionally presented on the Y axis
-if purpose is to predict one variable based on knowledge of the other, the citerion variable
is the one to be predicted whereas the predictor variable is the one from which the
prediction is made
-where the distinction is not obvious, it is irrelevant which variable is labelled x and which
Y
-regression line is the line of best fit drawn through a scatterplot, represent our best
prediction of Yi for a given value of X
-given any specified value of X, the corresponding height of the regression line represents
our best prediction of Y (ŷ)
Document Summary
When we are dealing with the relationship between two variables, we are concerned with correlation, and our measure of the degree or strength of this relationship is represented by a correlation coeeficient. Every experimental subject or unit or observation in the study is represented by a point in. The coordinates of this point (xi, yi) are the individual"s scores on variables x and y. Predictor variable/independent variable is traditionally presented on the x axis. Criterion variable/dependent variable traditionally presented on the y axis. If purpose is to predict one variable based on knowledge of the other, the citerion variable is the one to be predicted whereas the predictor variable is the one from which the prediction is made. Where the distinction is not obvious, it is irrelevant which variable is labelled x and which. Regression line is the line of best fit drawn through a scatterplot, represent our best prediction of yi for a given value of x.
