n=7, ∑x=52, ∑y=37, ∑x2=440, ∑y2=225, ∑xy=314,
(x̄=7.43, ȳ=5.29) r=0.9845. This correlation coefficient shows that there is a very good relationship between the x and y values, that is, when plotted, the graph of y against x is almost a straight line. As x increases so does y increase. (If you tabulate the x and y values you can confirm that the given sums are correct. Excel is useful in this exercise.)
correlation coefficient, r=(n∑xy-∑x∑y)/(√[(n∑x2-(∑x)2)(n∑y2-(∑y)2)]. Plug in the statistics as shown to get r.
∑ means sum of. For example, ∑xy means the sum of the product of paired x and y values; ∑y means the sum of all the y values.