condition mean min max ZT0-3 15.744766666666667 11.0115 18.97285 ZT4-7 7.46338 7.46338 7.46338 ZT8-11 8.364005 8.364005 8.364005 ZT12-15 12.67659 11.766829999999999 13.58635 ZT16-19 14.120550000000001 14.120550000000001 14.120550000000001 ZT20-23 23.482100000000003 23.482100000000003 23.482100000000003