condition mean min max ZT0-3 5.77008 5.77008 5.77008 ZT4-7 5.21075 5.21075 5.21075 ZT8-11 6.2684 6.2684 6.2684 ZT12-15 6.504475 6.504475 6.504475 ZT16-19 7.341480000000001 7.341480000000001 7.341480000000001 ZT20-23 6.06215 6.06215 6.06215