condition mean min max ZT0-3 4.986205 4.624275 5.3623899999999995 ZT4-7 3.1606050000000003 3.1606050000000003 3.1606050000000003 ZT8-11 3.15383 3.15383 3.15383 ZT12-15 5.043514999999999 4.898305 5.188725 ZT16-19 3.6060049999999997 3.6060049999999997 3.6060049999999997 ZT20-23 5.917585 5.917585 5.917585