condition mean min max ZT0-3 7.638511666666666 5.320905 9.659044999999999 ZT4-7 4.65729 4.65729 4.65729 ZT8-11 9.025694999999999 9.025694999999999 9.025694999999999 ZT12-15 8.4600925 8.431865 8.48832 ZT16-19 11.770365 11.770365 11.770365 ZT20-23 10.684605000000001 10.684605000000001 10.684605000000001