condition mean min max ZT0-3 6.265305 6.265305 6.265305 ZT4-7 4.938595 4.938595 4.938595 ZT8-11 2.828726 2.828726 2.828726 ZT12-15 5.24581 5.24581 5.24581 ZT16-19 8.60486 8.60486 8.60486 ZT20-23 10.439955000000001 10.439955000000001 10.439955000000001