def estimate_norm(X):
    """Estimates the mean and standard deviation from a data set

    Parameters:

        X : numpy.ndarray
            A 2D numpy ndarray in which the rows represent examples while the
            columns, features of the data you want to estimate normalization
            parameters on

    Returns: 
        numpy.ndarray,
                A 1D numpy ndarray containing the estimated mean over
                dimension 1 (columns) of the input data X

        numpy.ndarray,
                A 1D numpy ndarray containing the estimated unbiased standard deviation
                over dimension 1 (columns) of the input data X

    """
    return X.mean(axis=0), X.std(axis=0, ddof=1)