condition mean min max ZT0-3 3.7233324999999997 3.2577249999999998 4.18894 ZT4-7 3.007915 3.007915 3.007915 ZT8-11 4.27197 4.27197 4.27197 ZT12-15 0 0 0 ZT16-19 6.515195 6.515195 6.515195 ZT20-23 5.61116 5.61116 5.61116