condition mean min max ZT0-3 10.777845 8.92704 12.62865 ZT4-7 7.58003 7.58003 7.58003 ZT8-11 2.743355 2.743355 2.743355 ZT12-15 0 0 0 ZT16-19 7.843975 7.843975 7.843975 ZT20-23 9.640225 9.640225 9.640225