condition mean min max ZT0-3 12.019415 11.20508 12.83375 ZT4-7 10.68727 10.68727 10.68727 ZT8-11 24.7531 24.7531 24.7531 ZT12-15 0 0 0 ZT16-19 22.433 22.433 22.433 ZT20-23 16.42675 16.42675 16.42675