def get_max_tail_check(y_Arai, y_tail, t_Arai, tail_temps, n_tail):
    """
    input: y_Arai, y_tail, t_Arai, tail_temps, n_tail
    output: max_check, diffs
    """
    if not n_tail:
        return float('nan'), []
    tail_compare = []
    y_Arai_compare = []
    for temp in tail_temps[:n_tail]:
        tail_index = list(tail_temps).index(temp)
        tail_check = y_tail[tail_index]
        tail_compare.append(tail_check)
        arai_index = list(t_Arai).index(temp)
        nrm_orig = y_Arai[arai_index]
        y_Arai_compare.append(nrm_orig)
    diffs = numpy.array(y_Arai_compare) - numpy.array(tail_compare)
    abs_diffs = abs(diffs)
    max_check = max(abs_diffs)
    return max_check, diffs