correcoef

correcoef(matrix1: any[] | Mat, matrix2: any[] | Mat): number

param matrix1 - the first part of the pair of data to find the correlation coefficient of. Needs to be an Array or Mat.

param matrix2 - similar to matrix1, needs to be the same length and is an Array or Mat holding data.

returns - a number representing the correlation coefficient of matrix1 and matrix2, between -1 and 1.

The correlation coefficient can be thought of as a number that represents how strongly 2 variables are connected. It takes in two variables of data, matrix1 and matrix2, where matrix1 contains data, say [0,1,1,2,2,3] and matrix2 contains other data, say [0,0,1,1,2,3,].

Then it finds the distances between each point for each indice and keeps a track of it as a sum.

Overall, it outputs a number between -1 and 1. The closer it is to 1, the stronger the correlation. The closer to -1, the stronger the inverse correlation.

A practical use of this is something like an Array of housing prices over a span of years - matrix1, and an Array of crime amount over the years - matrix2. Is crime correlated to housing prices? If so, how much is it correlated?

To find the correlation coefficient of the two input matrices, use the following formula (or this function!):

$$r = \frac{\sum(x_i - \bar{x}) (y_i - \bar{y})}{\sqrt{\sum(x_i - \bar{x})^2 \sum(y_i - \bar{y})^2}}$$