condition mean min max ZT0-3 12.474626666666667 9.62528 14.38085 ZT4-7 6.6185 6.6185 6.6185 ZT8-11 6.021725 6.021725 6.021725 ZT12-15 7.0254224999999995 6.955165 7.09568 ZT16-19 7.915184999999999 7.915184999999999 7.915184999999999 ZT20-23 11.13455 11.13455 11.13455