ABSTRACT
This chapter explores linear correlation and the meaning of values obtained calculating the coefficient of correlation. For linear correlation, if points are plotted on a graph and all the points lie on a straight line, then perfect linear correlation is said to exist. When a straight line having a positive gradient can reasonably be drawn through points on a graph, positive or direct linear correlation exists. Similarly, when a straight line having a negative gradient can reasonably be drawn through points on a graph, negative or inverse linear correlation exists. A Pearson product-moment correlation attempts to draw a line of best fit through the data of two variables, and the Pearson correlation coefficient, r, indicates how far away all these data points are to this line of best fit. When the value of the coefficient of correlation has been obtained from the product moment formula, some care is needed before coming to conclusions based on this result.
