condition mean min max ZT0-3 7.274058 7.274058 7.274058 ZT4-7 8.0138745 8.0138745 8.0138745 ZT8-11 9.6267645 9.6267645 9.6267645 ZT12-15 8.290931 8.290931 8.290931 ZT16-19 9.343988 9.343988 9.343988 ZT20-23 8.3393535 8.3393535 8.3393535