condition mean min max ZT0-3 8.102494 8.102494 8.102494 ZT4-7 8.502293 8.502293 8.502293 ZT8-11 7.294252999999999 7.294252999999999 7.294252999999999 ZT12-15 7.749889 7.749889 7.749889 ZT16-19 7.4794465 7.4794465 7.4794465 ZT20-23 8.9501155 8.9501155 8.9501155