condition mean min max ZT0-3 17.980173 17.980173 17.980173 ZT4-7 23.9311785 23.9311785 23.9311785 ZT8-11 19.8246225 19.8246225 19.8246225 ZT12-15 16.6721775 16.6721775 16.6721775 ZT16-19 15.708344 15.708344 15.708344 ZT20-23 18.018375499999998 18.018375499999998 18.018375499999998