condition mean min max ZT0-3 17.524775 15.549400000000002 19.50015 ZT4-7 15.7395 15.7395 15.7395 ZT8-11 8.723285 8.723285 8.723285 ZT12-15 0 0 0 ZT16-19 8.51033 8.51033 8.51033 ZT20-23 12.60035 12.60035 12.60035