condition mean min max ZT0-3 8.5859425 8.14659 9.025295 ZT4-7 8.68023 8.68023 8.68023 ZT8-11 6.20803 6.20803 6.20803 ZT12-15 0 0 0 ZT16-19 17.3617 17.3617 17.3617 ZT20-23 15.928149999999999 15.928149999999999 15.928149999999999