condition mean min max ZT0-3 4.295705 4.295705 4.295705 ZT4-7 1.270351 1.270351 1.270351 ZT8-11 13.6816 13.6816 13.6816 ZT12-15 25.19015 25.19015 25.19015 ZT16-19 31.604100000000003 31.604100000000003 31.604100000000003 ZT20-23 8.60392 8.60392 8.60392