However , smokers using plain cigarette packs rated the experience of using the pack more negatively ( -0.52 , 95 % CI -0.82 to -0.22 , p = 0.001 ) , rated the pack attributes more negatively ( -1.59 , 95 % CI -1.80 to -1.39 , p < 0.001 ) , and rated the health warning as more impactful ( +0.51 , 95 % CI 0.24 to 0.78 , p < 0.001 ) .