(S1, M, N)
return S1 - lamb / (1 - lamb) * (1 - S1)
Unskew the sensivity indice
    (Jean-Yves Tissot, Clémentine Prieur (2012) "Bias correction for the
    estimation of sensitivity indices based on random balance designs.",
    Reliability Engineering and System Safety, Elsevier, 107, 205-213.
    doi:10.1016/j.ress.2012.06.010)
Unskew the sensivity indice
    (Jean-Yves Tissot, Clémentine Prieur (2012) "Bias correction for the
    estimation of sensitivity indices based on random balance designs.",
    Reliability Engineering and System Safety, Elsevier, 107, 205-213.
    doi:10.1016/j.ress.2012.06.010)
Unskew the sensivity indice ( Jean - Yves Tissot Clémentine Prieur ( 2012 ) Bias correction for the estimation of sensitivity indices based on random balance designs . Reliability Engineering and System Safety Elsevier 107 205 - 213 . doi : 10 . 1016 / j . ress . 2012 . 06 . 010 )
def unskew_S1(S1, M, N):
    """
    Unskew the sensivity indice
    (Jean-Yves Tissot, Clémentine Prieur (2012) "Bias correction for the
    estimation of sensitivity indices based on random balance designs.",
    Reliability Engineering and System Safety, Elsevier, 107, 205-213.
    doi:10.1016/j.ress.2012.06.010)
    """
    lamb = (2 * M) / N
    return S1 - lamb / (1 - lamb) * (1 - S1)
def unskew_S1 ( S1 , M , N ) : lamb = ( 2 * M ) / N return S1 - lamb / ( 1 - lamb ) * ( 1 - S1 )