condition mean min max ZT0-3 9.756525 9.756525 9.756525 ZT4-7 8.434905 8.434905 8.434905 ZT8-11 8.26118 8.26118 8.26118 ZT12-15 10.08119 10.08119 10.08119 ZT16-19 11.3422 11.3422 11.3422 ZT20-23 9.22991 9.22991 9.22991