condition mean min max ZT0-3 6.038885 6.038885 6.038885 ZT4-7 5.78382 5.78382 5.78382 ZT8-11 7.477025 7.477025 7.477025 ZT12-15 4.40348 4.40348 4.40348 ZT16-19 10.18281 10.18281 10.18281 ZT20-23 4.7630099999999995 4.7630099999999995 4.7630099999999995