condition mean min max ZT0-3 8.4477125 8.28803 8.607395 ZT4-7 8.30282 8.30282 8.30282 ZT8-11 8.28871 8.28871 8.28871 ZT12-15 0 0 0 ZT16-19 8.417815000000001 8.417815000000001 8.417815000000001 ZT20-23 7.897895 7.897895 7.897895