ljungBox function
Implementation
LjungBoxResult ljungBox(List<double> resid, int h, {int nParams = 0}) {
final n = resid.length;
final rho = acf(resid, h);
double Q = 0.0;
for (int k = 1; k <= h; k++) {
Q += (rho[k] * rho[k]) / (n - k);
}
Q *= n * (n + 2);
final df = math.max(1, h - nParams);
final p = chiSquareSF(Q, df);
return LjungBoxResult(Q, df, p);
}