condition mean min max ZT0-3 13.795167 13.795167 13.795167 ZT4-7 14.8197165 14.8197165 14.8197165 ZT8-11 15.167554 15.167554 15.167554 ZT12-15 14.266570999999999 14.266570999999999 14.266570999999999 ZT16-19 17.6160975 17.6160975 17.6160975 ZT20-23 15.599479500000001 15.599479500000001 15.599479500000001