condition mean min max ZT0-3 5.12906 5.12906 5.12906 ZT4-7 5.50483 5.50483 5.50483 ZT8-11 4.48726 4.48726 4.48726 ZT12-15 4.1628799999999995 4.1628799999999995 4.1628799999999995 ZT16-19 5.506905 5.506905 5.506905 ZT20-23 6.898675 6.898675 6.898675