
Correlations
 are "measures of association"
 a measurement of linear (straight line) relationship

measure of association
 a number that measures how related two variables are
 when two variables are related, this means that when one changes, the other changes

Pearson's product moment correlation
 the most common correlation
 referred to as "the correlation"
 it is used with quantitative (numerical) variables
 the symbol is r

Linear relationship
 most common
 correlation lies between 1 and 1
 the measure of how close the points in the scatterplot are to the best fitting straight line
 it's negative when the line goes down, positive when the line goes up, and 0 when the line is flat

regression line
the best fitting straight line

square of correlation
 r2
 sometimes called "variance accounted for" or "shared variance"
 it is interpreted as the amount of variance in the y variable accounted for by the x variable

residual
error in the prediction

regression and correlation
 yeild three important numbers:
 slope of best fitting line
 intercept of best fitting line
 correlation

