condition mean min max ZT0-3 11.0 11.0 11.0 ZT4-7 2.3 2.3 2.3 ZT8-11 32.6 32.6 32.6 ZT12-15 10.55 10.55 10.55 ZT16-19 7.7 7.7 7.7 ZT20-23 11.1 11.1 11.1