condition mean min max ZT0-3 27.778606 27.778606 27.778606 ZT4-7 24.054888 24.054888 24.054888 ZT8-11 24.871418 24.871418 24.871418 ZT12-15 24.0086625 24.0086625 24.0086625 ZT16-19 22.226264999999998 22.226264999999998 22.226264999999998 ZT20-23 25.9209675 25.9209675 25.9209675