condition mean min max ZT0-3 5.839838333333334 4.39344 6.6066400000000005 ZT4-7 4.394245 4.394245 4.394245 ZT8-11 4.1690249999999995 4.1690249999999995 4.1690249999999995 ZT12-15 5.997785 5.343185 6.652385 ZT16-19 4.9153649999999995 4.9153649999999995 4.9153649999999995 ZT20-23 7.009055 7.009055 7.009055