condition mean min max ZT0-3 14.542312 14.542312 14.542312 ZT4-7 15.4645865 15.4645865 15.4645865 ZT8-11 15.735486000000002 15.735486000000002 15.735486000000002 ZT12-15 15.2242905 15.2242905 15.2242905 ZT16-19 13.679420499999999 13.679420499999999 13.679420499999999 ZT20-23 14.465705 14.465705 14.465705