def standardize_columns(colgroup):
    """
    Standardize group of columns together
    colgroup: Pandas.DataFrame
    returns: Pandas.DataFrames: Colum Group standardized, Mean of the colgroup, stddeviation of the colgroup
    """
    _me = np.mean(colgroup.values.flatten())
    centered = colgroup.sub(_me)
    me = pd.DataFrame(np.full(len(colgroup.columns),_me), index=colgroup.columns)

    _st = np.std(colgroup.values.flatten())
    standardized = centered.div(_st)
    st = pd.DataFrame(np.full(len(colgroup.columns),_st), index=colgroup.columns)