condition mean min max ZT0-3 6.622455 6.622455 6.622455 ZT4-7 4.709135 4.709135 4.709135 ZT8-11 5.992885 5.992885 5.992885 ZT12-15 5.468885 5.468885 5.468885 ZT16-19 7.46355 7.46355 7.46355 ZT20-23 6.515935 6.515935 6.515935