condition mean min max ZT0-3 4.667435 4.337095 4.997775000000001 ZT4-7 12.82599 12.82599 12.82599 ZT8-11 6.80232 6.80232 6.80232 ZT12-15 0 0 0 ZT16-19 9.24723 9.24723 9.24723 ZT20-23 11.28845 11.28845 11.28845