condition mean min max ZT0-3 37.036525 35.27915 38.7939 ZT4-7 31.56545 31.56545 31.56545 ZT8-11 38.7928 38.7928 38.7928 ZT12-15 0 0 0 ZT16-19 45.63865 45.63865 45.63865 ZT20-23 49.84105 49.84105 49.84105