condition mean min max ZT0-3 8.42165 8.35357 8.489730000000002 ZT4-7 6.702395 6.702395 6.702395 ZT8-11 5.79205 5.79205 5.79205 ZT12-15 0 0 0 ZT16-19 8.284295 8.284295 8.284295 ZT20-23 7.129085 7.129085 7.129085