condition mean min max ZT0-3 3.19318 3.19318 3.19318 ZT4-7 3.242755 3.242755 3.242755 ZT8-11 3.084275 3.084275 3.084275 ZT12-15 4.939 4.939 4.939 ZT16-19 6.093389999999999 6.093389999999999 6.093389999999999 ZT20-23 7.3554 7.3554 7.3554