condition mean min max ZT0-3 8.439995 8.439995 8.439995 ZT4-7 6.724915 6.724915 6.724915 ZT8-11 5.745245 5.745245 5.745245 ZT12-15 5.320785000000001 5.320785000000001 5.320785000000001 ZT16-19 7.366149999999999 7.366149999999999 7.366149999999999 ZT20-23 7.55575 7.55575 7.55575