condition mean min max ZT0-3 1.3245906666666667 0.574527 2.449345 ZT4-7 2.9392449999999997 2.9392449999999997 2.9392449999999997 ZT8-11 0.493975 0.493975 0.493975 ZT12-15 0.616995 0.44517150000000005 0.7888185 ZT16-19 0.40329099999999996 0.40329099999999996 0.40329099999999996 ZT20-23 0.22676849999999998 0.22676849999999998 0.22676849999999998