condition mean min max ZT0-3 8.60383 8.60383 8.60383 ZT4-7 6.17528 6.17528 6.17528 ZT8-11 7.98588 7.98588 7.98588 ZT12-15 9.774905 9.774905 9.774905 ZT16-19 11.988800000000001 11.988800000000001 11.988800000000001 ZT20-23 9.933385000000001 9.933385000000001 9.933385000000001