condition mean min max ZT0-3 20.63362329 20.289427879999998 20.9778187 ZT4-7 15.6055457675 13.444033665 17.767057870000002 ZT8-11 22.33471675 20.52398746 24.14544604 ZT12-15 30.944328287500003 24.06753167 37.821124905000005 ZT16-19 33.879183995 31.928796929999997 35.82957106 ZT20-23 37.1060942 36.528541770000004 37.68364663