def indexAvg(ser):
    """ This function is used to calculate average point. 
        It used to the agree/disagree multiple choice. 

    Args:
        ser (pandas.Series): Source data

    Returns:
        double: average point
        precision is 2. 
    """    

    length = ser.size
    indexSum = 0
    for i in ser:
        indexSum += i
    return round(indexSum / length, 2)