Look up the calculated value of r in a table of critical values of the correlation coefficient . If the calculated value of r is less than the critical value of r, accept the null hypothesis - there is no proof of an association between the variables. If one variable depends on another, i.e. there is a causal relationship, then it is always possible to find some kind of correlation between the two variables. However, if both variables depend on a third, they can show a sizeable correlation without any causal dependency between them. Correlation is also one of the tools available on the Excel Analysis ToolPak .
Correlation quantifies how closely two variables are connected.
Calculate the test statistics. Use the MSExcel Analysis ToolPak Regression option. An important statistic - equivalent to the r value from a correlation test, shows how closely X and Y are related. The r 2 value tells you how much your ability to predict is improved by using the regression line, compared with not using it. The least possible improvement is 0, i.e. the regression line does not help at all.