condition mean min max ZT0-3 6.7878799999999995 6.7878799999999995 6.7878799999999995 ZT4-7 5.65681 5.65681 5.65681 ZT8-11 5.670590000000001 5.670590000000001 5.670590000000001 ZT12-15 6.31186 6.31186 6.31186 ZT16-19 7.112793333333333 7.112793333333333 7.112793333333333 ZT20-23 7.07315 7.07315 7.07315