condition mean min max ZT0-3 3.2262833333333334 1.942955 5.06263 ZT4-7 6.675615 6.675615 6.675615 ZT8-11 3.76142 3.76142 3.76142 ZT12-15 4.4312575 4.15817 4.704345 ZT16-19 3.600525 3.600525 3.600525 ZT20-23 2.849325 2.849325 2.849325