Sum of Cross Products
Given a set of pairs of numbers, the sum of the cross products is computed by taking the product of each pair of numbers and summing these products. For the data,
1 3 4 6 7 9 1 1
the sum of cross products is: 1 x 3 + 4 x 6 + 7 x 9 + 1 x 1 = 91.