condition mean min max ZT0-3 1.373238 1.206861 1.539615 ZT4-7 0.8944225 0.8944225 0.8944225 ZT8-11 0.951681 0.951681 0.951681 ZT12-15 0 0 0 ZT16-19 1.28099 1.28099 1.28099 ZT20-23 1.5717789999999998 1.5717789999999998 1.5717789999999998