condition mean min max ZT0-3 20.974319 20.974319 20.974319 ZT4-7 24.448426499999997 24.448426499999997 24.448426499999997 ZT8-11 24.067027 24.067027 24.067027 ZT12-15 31.6919135 31.6919135 31.6919135 ZT16-19 34.632645000000004 34.632645000000004 34.632645000000004 ZT20-23 33.3623065 33.3623065 33.3623065