condition mean min max ZT0-3 8.948263 8.948263 8.948263 ZT4-7 8.8565365 8.8565365 8.8565365 ZT8-11 9.0530515 9.0530515 9.0530515 ZT12-15 7.693569 7.693569 7.693569 ZT16-19 9.167179 9.167179 9.167179 ZT20-23 9.578067 9.578067 9.578067