condition mean min max ZT0-3 6.598295 5.27234 7.924250000000001 ZT4-7 3.9873649999999996 3.9873649999999996 3.9873649999999996 ZT8-11 2.42844 2.42844 2.42844 ZT12-15 0 0 0 ZT16-19 5.883435 5.883435 5.883435 ZT20-23 8.082934999999999 8.082934999999999 8.082934999999999