condition mean min max ZT0-3 9.42787 9.42787 9.42787 ZT4-7 5.10185 5.10185 5.10185 ZT8-11 5.07036 5.07036 5.07036 ZT12-15 7.23485 7.23485 7.23485 ZT16-19 11.3202 11.3202 11.3202 ZT20-23 11.27425 11.27425 11.27425