condition mean min max ZT0-3 6.75 6.75 6.75 ZT4-7 23.5 23.5 23.5 ZT8-11 15.15 15.15 15.15 ZT12-15 9.149999999999999 9.149999999999999 9.149999999999999 ZT16-19 14.15 14.15 14.15 ZT20-23 9.4 9.4 9.4