condition mean min max ZT0-3 1.386458 1.168619 1.6359934999999999 ZT4-7 1.93993 1.93993 1.93993 ZT8-11 2.3792 2.3792 2.3792 ZT12-15 2.6399575 1.66927 3.610645 ZT16-19 4.009195 4.009195 4.009195 ZT20-23 2.683825 2.683825 2.683825