mu_y = m mu_x + mu_z with mu_x = mu_z = 0, sigma_y = sqrt(m^2 sigma_x^2 + sigma_z^2) and r = m sigma_x / sigma_y. The defaults are the book's worked spread, sigma_y = 13.
mu_y = m mu_x + mu_z with mu_x = mu_z = 0, sigma_y = sqrt(m^2 sigma_x^2 + sigma_z^2) and r = m sigma_x / sigma_y. The defaults are the book's worked spread, sigma_y = 13.