condition mean min max ZT0-3 7.495548 7.495548 7.495548 ZT4-7 8.475356 8.475356 8.475356 ZT8-11 8.198100499999999 8.198100499999999 8.198100499999999 ZT12-15 8.17812 8.17812 8.17812 ZT16-19 8.3536965 8.3536965 8.3536965 ZT20-23 7.53268 7.53268 7.53268