condition mean min max ZT0-3 13.734721666666667 8.268965 17.0759 ZT4-7 6.718665 6.718665 6.718665 ZT8-11 17.25975 17.25975 17.25975 ZT12-15 19.134549999999997 19.088549999999998 19.18055 ZT16-19 11.159144999999999 11.159144999999999 11.159144999999999 ZT20-23 11.8421 11.8421 11.8421