condition mean min max ZT0-3 8.428096666666667 5.501455 10.59834 ZT4-7 2.045925 2.045925 2.045925 ZT8-11 1.48433 1.48433 1.48433 ZT12-15 4.874495 4.519565 5.229425 ZT16-19 3.369975 3.369975 3.369975 ZT20-23 7.026325 7.026325 7.026325