condition mean min max ZT0-3 9.17727 9.17727 9.17727 ZT4-7 7.10186 7.10186 7.10186 ZT8-11 7.770625 7.770625 7.770625 ZT12-15 7.96264 7.96264 7.96264 ZT16-19 11.486049999999999 11.486049999999999 11.486049999999999 ZT20-23 9.166174999999999 9.166174999999999 9.166174999999999