condition mean min max ZT0-3 22.31935 22.31935 22.31935 ZT4-7 18.847050000000003 18.847050000000003 18.847050000000003 ZT8-11 8.904955 8.904955 8.904955 ZT12-15 7.967264999999999 7.967264999999999 7.967264999999999 ZT16-19 14.65235 14.65235 14.65235 ZT20-23 19.77095 19.77095 19.77095