condition mean min max ZT0-3 17.72435 17.72435 17.72435 ZT4-7 22.946150000000003 22.946150000000003 22.946150000000003 ZT8-11 13.59185 13.59185 13.59185 ZT12-15 8.172125000000001 8.172125000000001 8.172125000000001 ZT16-19 8.286840000000002 8.286840000000002 8.286840000000002 ZT20-23 11.0604 11.0604 11.0604