STA-1013 Lecture Notes - Lecture 7: Standard Deviation, Scatter Plot
Document Summary
Scatter diagram (scatterplot)- a graph in which each point represents the values of two variables. Measuring the strength of a correlation: statisticians measure the strength of a correlation with a number called the correlation coefficient, represented by the letter r. Properties of the correlation coefficient, r: the correlation coefficient, r, is a measure of the strength of a correlation. Its value can range only from -1 to 1. If there is no correlation, the points do not follow any ascending or descending straight-line pattern, and the value of r is close to 0. If there is a positive correlation, the correlation coefficient is positive (0 < r 1): A perfect positive correlation (in which all the points on a scatter diagram lie on an ascending straight line) has a correlation coefficient r = 1. Values of r close to 1 mean a strong positive correlation and positive values closer to 0 mean a weak positive correlation.
