condition mean min max ZT0-3 38.75 38.75 38.75 ZT4-7 4.3 4.3 4.3 ZT8-11 7.4 7.4 7.4 ZT12-15 6.45 6.45 6.45 ZT16-19 15.149999999999999 15.149999999999999 15.149999999999999 ZT20-23 14.5 14.5 14.5