condition mean min max ZT0-3 8.257785 7.4215800000000005 9.09399 ZT4-7 7.530215 7.530215 7.530215 ZT8-11 7.517745 7.517745 7.517745 ZT12-15 0 0 0 ZT16-19 7.77812 7.77812 7.77812 ZT20-23 7.35859 7.35859 7.35859