VAR Coefficient Estimate

Problem

Estimate a VAR(1) slope coefficient by ordinary least squares, regressing y_current on x_lag: sum((x - mean_x) * (y - mean_y)) / sum((x - mean_x)^2).

Return 0.0 if the lists are empty, have different lengths, or x_lag is constant.

Hint

This is the lag-one cross coefficient of a bivariate VAR.

case 1

in: [[1,2,3,4],[2,4,6,8]]

expected: 2

case 2

in: [[1,2,3,4],[0,1,2,3]]

expected: 1

case 3

in: [[1,1,1],[2,3,4]]

expected: 0

case 4

in: [[0,1,2],[1,1,1]]

expected: 0

Starter codePython

def var1_coefficient_estimate(x_lag, y_current):
    # Your code here
    pass

4 test cases · run your code against them in the editor