condition mean min max ZT0-3 0.421269 0.421269 0.421269 ZT4-7 0.328727 0.328727 0.328727 ZT8-11 0.358441 0.358441 0.358441 ZT12-15 0.368031 0.368031 0.368031 ZT16-19 0.40384549999999997 0.40384549999999997 0.40384549999999997 ZT20-23 0.350089 0.350089 0.350089