■ Data input (xi, yi : data, n : number of data)
※ If the number of data is less than 10, enter all remaining values ​​as 0.

▶ average of x, xa = (∑ xi)/n

▶ average of y, ya = (∑ yi)/n

▶ Sxy = ∑(xi-xa)*(yi-ya)

※ The length of a formula is long and thus divided for calculation.  Since xa * ya is added by times of the number of data of 0, so subtract that amount.

▶ Sx2 = ∑(xi-xa)^2

※ Since xa^2 is added by times of the number of data of 0, so subtract that amount.
▶ Sy2 = ∑(yi-ya)^2

※ Since ya^2 is added by times of the number of data of 0, so subtract that amount.

▶ 피어슨 상관 계수를 구함.