condition mean min max ZT0-3 11.074471 11.074471 11.074471 ZT4-7 9.5780405 9.5780405 9.5780405 ZT8-11 11.032948000000001 11.032948000000001 11.032948000000001 ZT12-15 10.3090835 10.3090835 10.3090835 ZT16-19 11.2299615 11.2299615 11.2299615 ZT20-23 12.976243 12.976243 12.976243