condition mean min max ZT0-3 7.58671 6.504225 8.669195 ZT4-7 12.7593 12.7593 12.7593 ZT8-11 18.3859 18.3859 18.3859 ZT12-15 0 0 0 ZT16-19 19.8983 19.8983 19.8983 ZT20-23 12.72165 12.72165 12.72165