Linear Regression CALCULATOR: Write the equation of the Linear Regression. line of best fit A ___________ is “our attempt” at fitting a line to the data. Enter x-values into L 1. Enter y-values into L 2. 1. A Linear Regression is the calculator’s _____. line of best fit STAT Button 2. It is based on calculations involving residuals (see residual notes). It is the ____________. BEST line of best fit ENTER twice. REMEMBER: y = mx + b The calculator uses: a = slope b = y-int y = ax + b slope y-intercept ------ Correlation Coefficient 3.
Correlation Coefficient The correlation coefficient (r) measures the strength direction _______ and tells you the __________of a linear relationship between two variables. It tells us how well fits the data. the line _____ What is the Correlation Coefficient of each Linear Regression? How well does each line fit the data? 1. Just like correlation can be positive and negative, positive negative r will be ________ or ________ as well. HOW TO INTERPRET: ·The closer r is to +1 or -1, the better the line “fits” 2. the data ·Values of r close to O (zero) indicate a poor “fit. ” CAUSATION BE CAREFUL! Just because there may be a strong correlation between the two variables, there is NO cause or effect IMPLICATION about _____________. Just because two variables tend to increase or decrease together does NOT mean a change in one is CAUSING a change in the other. 3.