def scale_errors(cov_axes, confidence_level=0.95):
    """
    Returns major axes of error ellipse or
    hyperbola, rescaled using chi2 test statistic
    """
    dof = len(cov_axes)
    x2t = chi2.ppf(confidence_level,dof)
    return N.sqrt(x2t*cov_axes)
Returns major axes of error ellipse or
    hyperbola, rescaled using chi2 test statistic