Correlation Coefficient (r) r > 0.8 Strong positive linear relationship 0.8 < r < 0.5 Moderate positive linear relationship 0.5 < r < 0.2 Weak positive linear relationship Correlation Coefficient (r)

Correlation Coefficient 0.2 < r < -0.2 No linear relationship -0.2 < r < -0.5 Weak negative linear relationship -0.5 < r < -0.7 Moderate negative linear relationship -0.7 < r < -1.0 Strong negative linear relationship Correlation Coefficient

Correlation Coefficient Using calculator Stat menu Enter data in list Calc Reg X r = Correlation Coefficient

Correlation Coefficient x 2 3 4 6 8 9 10 y 20 18 17 16 14 12 11 x 2 4 5 7 9 10 11 15 y 3 6 Correlation Coefficient

r = -0.987 r = +0.9686

Question 1, page 580 Question

Product Moment Correlation Coefficient r = Sxy/SxSy Sxy is called the covarience of x and y Sx is the standard deviation of x Sy is the standard deviation of y Product Moment Correlation Coefficient

Line of best fit The “by eye” method Using the locus of means Method of least squares (linreg- calculator Line of best fit

Finding the line of best fit x 2 4 5 7 9 10 11 15 y 3 6 Finding the line of best fit