condition mean min max ZT0-3 8.8154005295 8.731253298 8.899547761000001 ZT4-7 7.167078952499999 6.637356210999999 7.6968016939999995 ZT8-11 6.9415363821666665 5.618169832666666 8.264902931666667 ZT12-15 6.436369865166666 5.785774231333333 7.086965499000001 ZT16-19 7.5430850595 6.888312200333333 8.197857918666667 ZT20-23 7.1108150855000005 5.601428183666667 8.620201987333333