condition mean min max ZT0-3 23.166657 23.166657 23.166657 ZT4-7 20.886178 20.886178 20.886178 ZT8-11 22.358999 22.358999 22.358999 ZT12-15 19.915521499999997 19.915521499999997 19.915521499999997 ZT16-19 21.6890485 21.6890485 21.6890485 ZT20-23 21.440758000000002 21.440758000000002 21.440758000000002