condition mean min max ZT0-3 1.11088233625 0.992295567 1.2294691055 ZT4-7 0.8487173561666667 0.838292682 0.8591420303333334 ZT8-11 0.7397121069999999 0.5717568789999999 0.907667335 ZT12-15 0.6703439819999999 0.574607998 0.766079966 ZT16-19 0.42338045 0.332424616 0.514336284 ZT20-23 0.6629324273333332 0.572079087 0.7537857676666666