For 20 cities, ∑x=214.5\sum x=214.5∑x=214.5, ∑y=107.6\sum y=107.6∑y=107.6, ∑x2=2367.8\sum x^2=2367.8∑x2=2367.8, ∑y2=665.3\sum y^2=665.3∑y2=665.3 and ∑xy=1081.2\sum xy=1081.2∑xy=1081.2.
Calculate the product-moment correlation coefficient.