condition mean min max ZT0-3 3.2973729487499996 2.784251088 3.8104948094999997 ZT4-7 8.145878634 7.106951248500001 9.1848060195 ZT8-11 6.34147856925 5.9443739945 6.738583144 ZT12-15 5.4261727437500005 4.009867936000001 6.8424775515 ZT16-19 10.3229671 8.094825972999999 12.551108227 ZT20-23 23.96303542 20.04957994 27.8764909