y = mx + b Linear Regression line of best fit REMEMBER: A ______________________ is “our attempt” at fitting a line to the data. A Linear Regression is the calculator’s __________________. It is based on calculations involving residuals (see residual notes). It is the ________________________. REMEMBER: y = mx + b The calculator uses: y = ax + b a = slope b = y-int CALCULATOR: Enter x-values into L1. Enter y-values into L2. Button ENTER twice. Write the equation of the Linear Regression. 1. 2. 3. line of best fit STAT line of best fit BEST line of best fit slope y-intercept ------ Correlation Coefficient

Correlation Coefficient The correlation coefficient (r) measures the ______________ and tells you the ___________________of a linear relationship between two variables. It tells us how well the line _________ the data. Just like correlation can be positive and negative, r will be _______________ or _______________ as well. HOW TO INTERPRET: The closer r is Values of r CAUSATION BE CAREFUL! Just because there may be a strong correlation between the two variables, there is NO 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. What is the Correlation Coefficient of each Linear Regression? How well does each line fit the data? 1. 2. 3. strength direction fits positive negative to +1 or -1, the better the line “fits” the data close to O (zero) indicate a poor “fit.” cause or effect