Graph of a set of data points Used to evaluate the correlation between two variables
The line of best fit - a straight line that best represents the data on a scatter plot. This line may pass through some of the points, none of the points, or all of the points.
r measures the strength and direction of the relationship between 2 variables -1≤ r ≤1 A correlation greater than 0.8 is generally described as strong, whereas a correlation less than 0.5 is generally described as weak.
r is positive As x increases, y also increases If x and y have a strong positive linear correlation, r is close to 1
r is negative As x increases, y decreases If x and y have a strong negative linear correlation, r is close to -1
random, nonlinear relationship between the two variables Points show no pattern r is near zero
correlation coefficient, r = 1correlation coefficient, r = -1