condition mean min max ZT0-3 3.060225 3.060225 3.060225 ZT4-7 0.827895 0.827895 0.827895 ZT8-11 2.036047 2.036047 2.036047 ZT12-15 6.13291 6.13291 6.13291 ZT16-19 6.77683 6.77683 6.77683 ZT20-23 7.54738 7.54738 7.54738