condition mean min max ZT0-3 13.611684 13.611684 13.611684 ZT4-7 14.8903925 14.8903925 14.8903925 ZT8-11 16.839201 16.839201 16.839201 ZT12-15 14.7654795 14.7654795 14.7654795 ZT16-19 16.821811 16.821811 16.821811 ZT20-23 15.209712 15.209712 15.209712