condition mean min max ZT0-3 2.4721216666666668 1.76374 3.79659 ZT4-7 4.055215 4.055215 4.055215 ZT8-11 8.88083 8.88083 8.88083 ZT12-15 4.4619925 3.85876 5.065225 ZT16-19 2.72444 2.72444 2.72444 ZT20-23 2.6389449999999997 2.6389449999999997 2.6389449999999997