condition mean min max ZT0-3 16.049999999999997 16.049999999999997 16.049999999999997 ZT4-7 6.4 6.4 6.4 ZT8-11 7.75 7.75 7.75 ZT12-15 6.45 6.45 6.45 ZT16-19 14.75 14.75 14.75 ZT20-23 14.55 14.55 14.55