condition mean min max ZT0-3 1.9288871666666667 1.4919965 2.379105 ZT4-7 3.194365 3.194365 3.194365 ZT8-11 0.9339815 0.9339815 0.9339815 ZT12-15 1.98489275 1.980385 1.9894005 ZT16-19 0.8804115 0.8804115 0.8804115 ZT20-23 1.51944 1.51944 1.51944