condition mean min max ZT0-3 7.534841 7.534841 7.534841 ZT4-7 9.083443 9.083443 9.083443 ZT8-11 8.596184999999998 8.596184999999998 8.596184999999998 ZT12-15 7.848211 7.848211 7.848211 ZT16-19 9.758226 9.758226 9.758226 ZT20-23 8.5949895 8.5949895 8.5949895