condition mean min max ZT0-3 19.404975 17.869300000000003 20.94065 ZT4-7 4.51354 4.51354 4.51354 ZT8-11 0.9821854999999999 0.9821854999999999 0.9821854999999999 ZT12-15 0 0 0 ZT16-19 1.919472 1.919472 1.919472 ZT20-23 7.0696200000000005 7.0696200000000005 7.0696200000000005