condition mean min max ZT0-3 11.808677 11.808677 11.808677 ZT4-7 12.305253 12.305253 12.305253 ZT8-11 10.03302 10.03302 10.03302 ZT12-15 11.300507499999998 11.300507499999998 11.300507499999998 ZT16-19 9.5777605 9.5777605 9.5777605 ZT20-23 9.910955999999999 9.910955999999999 9.910955999999999