condition mean min max ZT0-3 7.142306 7.142306 7.142306 ZT4-7 7.650710500000001 7.650710500000001 7.650710500000001 ZT8-11 7.4929085 7.4929085 7.4929085 ZT12-15 7.97881 7.97881 7.97881 ZT16-19 7.646142 7.646142 7.646142 ZT20-23 8.525664 8.525664 8.525664