condition mean min max ZT0-3 13.291517 13.291517 13.291517 ZT4-7 13.3693635 13.3693635 13.3693635 ZT8-11 12.3906505 12.3906505 12.3906505 ZT12-15 11.6516495 11.6516495 11.6516495 ZT16-19 11.828623 11.828623 11.828623 ZT20-23 10.692340999999999 10.692340999999999 10.692340999999999