condition mean min max ZT0-3 6.414445000000001 6.414445000000001 6.414445000000001 ZT4-7 5.279375 5.279375 5.279375 ZT8-11 3.6686949999999996 3.6686949999999996 3.6686949999999996 ZT12-15 3.10518 3.10518 3.10518 ZT16-19 8.564350000000001 8.564350000000001 8.564350000000001 ZT20-23 8.36158 8.36158 8.36158