condition mean min max ZT0-3 8.932994 8.932994 8.932994 ZT4-7 9.138912 9.138912 9.138912 ZT8-11 9.0396675 9.0396675 9.0396675 ZT12-15 8.870175 8.870175 8.870175 ZT16-19 8.9108615 8.9108615 8.9108615 ZT20-23 11.441483 11.441483 11.441483