condition mean min max ZT0-3 22.97991 22.97991 22.97991 ZT4-7 17.676979 17.676979 17.676979 ZT8-11 21.134201 21.134201 21.134201 ZT12-15 20.270209 20.270209 20.270209 ZT16-19 22.523231000000003 22.523231000000003 22.523231000000003 ZT20-23 21.198738 21.198738 21.198738