def filter_outliers_from_series(ser):
    """
    remove values that are >= or <=  
    than 3 times the standard deviation from the mean.
    ser: pd.Series with numerical dytpe
    returns: filtered pd.Series
    """
    mu = ser.mean()
    std = ser.std()
    lower_limit = mu - (3*std)
    upper_limit = mu + (3*std)
    fltr = (ser >= lower_limit) & (ser <= upper_limit)
    
    return ser.loc[fltr]