condition mean min max ZT0-3 7.074618333333333 6.305949999999999 8.528144999999999 ZT4-7 7.27935 7.27935 7.27935 ZT8-11 4.369735 4.369735 4.369735 ZT12-15 8.3015825 7.004905 9.59826 ZT16-19 9.589235 9.589235 9.589235 ZT20-23 8.997995 8.997995 8.997995