condition mean min max ZT0-3 12.608234 12.608234 12.608234 ZT4-7 14.6802895 14.6802895 14.6802895 ZT8-11 11.3714695 11.3714695 11.3714695 ZT12-15 68.645587 68.645587 68.645587 ZT16-19 17.305704499999997 17.305704499999997 17.305704499999997 ZT20-23 32.8314615 32.8314615 32.8314615