condition mean min max ZT0-3 16.881069 16.881069 16.881069 ZT4-7 16.376417 16.376417 16.376417 ZT8-11 15.449137499999999 15.449137499999999 15.449137499999999 ZT12-15 17.3104455 17.3104455 17.3104455 ZT16-19 19.668492 19.668492 19.668492 ZT20-23 16.644688 16.644688 16.644688