condition mean min max ZT0-3 20.1 20.1 20.1 ZT4-7 13.7 13.7 13.7 ZT8-11 8.0 8.0 8.0 ZT12-15 40.849999999999994 40.849999999999994 40.849999999999994 ZT16-19 16.15 16.15 16.15 ZT20-23 7.45 7.45 7.45