condition mean min max ZT0-3 9.5602925 9.01594 10.104645 ZT4-7 8.826205 8.826205 8.826205 ZT8-11 8.043714999999999 8.043714999999999 8.043714999999999 ZT12-15 0 0 0 ZT16-19 10.5079 10.5079 10.5079 ZT20-23 9.303805 9.303805 9.303805