condition mean min max ZT0-3 16.881069 16.881069 16.881069 ZT4-7 18.53537 18.53537 18.53537 ZT8-11 18.327846 18.327846 18.327846 ZT12-15 16.504590999999998 16.504590999999998 16.504590999999998 ZT16-19 16.908962000000002 16.908962000000002 16.908962000000002 ZT20-23 15.412099999999999 15.412099999999999 15.412099999999999