condition mean min max ZT0-3 4.6953675 4.43679 4.953945 ZT4-7 4.13214 4.13214 4.13214 ZT8-11 4.2432099999999995 4.2432099999999995 4.2432099999999995 ZT12-15 6.25660375 5.795757500000001 6.7174499999999995 ZT16-19 5.401791666666666 4.77842 6.025163333333333 ZT20-23 0 0 0