condition mean min max ZT0-3 7.784836666666667 6.565535000000001 8.765075 ZT4-7 5.32776 5.32776 5.32776 ZT8-11 5.8449 5.8449 5.8449 ZT12-15 6.901875 6.144 7.65975 ZT16-19 6.97159 6.97159 6.97159 ZT20-23 8.217045 8.217045 8.217045