condition mean min max ZT0-3 17.261426 17.261426 17.261426 ZT4-7 34.936206 34.936206 34.936206 ZT8-11 41.249737999999994 41.249737999999994 41.249737999999994 ZT12-15 38.747671499999996 38.747671499999996 38.747671499999996 ZT16-19 18.9711795 18.9711795 18.9711795 ZT20-23 17.6115935 17.6115935 17.6115935