condition mean min max ZT0-3 8.849954 8.849954 8.849954 ZT4-7 9.6632695 9.6632695 9.6632695 ZT8-11 8.853576499999999 8.853576499999999 8.853576499999999 ZT12-15 9.151968499999999 9.151968499999999 9.151968499999999 ZT16-19 10.096365500000001 10.096365500000001 10.096365500000001 ZT20-23 10.064473 10.064473 10.064473