condition mean min max ZT0-3 18.689013 18.689013 18.689013 ZT4-7 18.4371185 18.4371185 18.4371185 ZT8-11 17.633352000000002 17.633352000000002 17.633352000000002 ZT12-15 16.602391 16.602391 16.602391 ZT16-19 20.806566 20.806566 20.806566 ZT20-23 19.525835999999998 19.525835999999998 19.525835999999998