Chapter 4 Correlation and regression stats

Correlation

measures the direction and strength of linear relationship between two quantitative variables

Regression

Expresses the relationship in the form of a mathematical equation

Purpose of correlation and regression?

Investigating relationships between two quantitative variables

Independent variable

input/explanatory variable

Dependent variable

output/response variable

Correlation Coefficient symbol

r

Correlation Coefficient

numerical value of the relationship between two variables

Linear regression equation

y=a+bx

a represent?

Intercept

b represents?

slope

Interpolation

predicted y based withing the observed range of x

Extrapolation

Predicted y based outside the range of x

Which is more reliable?

Interpolation

Coefficient of determination symbol

r^2

Coefficient of determination

Indicates the proportion of data in the dependent variable that's explained by the independent variable

Solving for explained variation?

rx100

Solving for unexplained variation?

100-explained variation%