condition mean min max ZT0-3 17.655871 17.655871 17.655871 ZT4-7 20.754479500000002 20.754479500000002 20.754479500000002 ZT8-11 17.4798955 17.4798955 17.4798955 ZT12-15 17.1953025 17.1953025 17.1953025 ZT16-19 17.547743 17.547743 17.547743 ZT20-23 15.475721 15.475721 15.475721