condition mean min max ZT0-3 7.9594675 7.71444 8.204495 ZT4-7 9.64494 9.64494 9.64494 ZT8-11 12.075700000000001 12.075700000000001 12.075700000000001 ZT12-15 0 0 0 ZT16-19 14.03295 14.03295 14.03295 ZT20-23 11.7304 11.7304 11.7304