condition mean min max ZT0-3 21.224200000000003 21.224200000000003 21.224200000000003 ZT4-7 17.21725 17.21725 17.21725 ZT8-11 19.551000000000002 19.551000000000002 19.551000000000002 ZT12-15 20.7932 20.7932 20.7932 ZT16-19 26.56025 26.56025 26.56025 ZT20-23 24.278100000000002 24.278100000000002 24.278100000000002