condition mean min max ZT0-3 3.1690775 2.851755 3.4864 ZT4-7 3.19523 3.19523 3.19523 ZT8-11 2.074459 2.074459 2.074459 ZT12-15 0 0 0 ZT16-19 5.31022 5.31022 5.31022 ZT20-23 2.75031 2.75031 2.75031