condition mean min max ZT0-3 8.594155 8.22545 8.96286 ZT4-7 6.8402899999999995 6.8402899999999995 6.8402899999999995 ZT8-11 6.605115 6.605115 6.605115 ZT12-15 0 0 0 ZT16-19 8.761225 8.761225 8.761225 ZT20-23 11.94565 11.94565 11.94565