condition mean min max ZT0-3 245.222245 245.222245 245.222245 ZT4-7 244.35418049999998 244.35418049999998 244.35418049999998 ZT8-11 211.520203 211.520203 211.520203 ZT12-15 248.0832975 248.0832975 248.0832975 ZT16-19 241.74016650000002 241.74016650000002 241.74016650000002 ZT20-23 234.7652025 234.7652025 234.7652025