condition mean min max ZT0-3 8.932269999999999 8.932269999999999 8.932269999999999 ZT4-7 7.6021 7.6021 7.6021 ZT8-11 6.7111149999999995 6.7111149999999995 6.7111149999999995 ZT12-15 8.339215 8.339215 8.339215 ZT16-19 10.516449999999999 10.516449999999999 10.516449999999999 ZT20-23 8.13114 8.13114 8.13114