To determine the effect of color on problem-solving performance, Diana conducted an experiment in which she varied only the color of anagrams (red, green, or black) and measured the number of anagrams solved. When analyzing data, she used an alpha level of .05. The results section of her report included the following statistical information about the effect of the color variable on anagrams solved: F(2, 57) = 7.35, p = .006. Based only on this description of the experiment and its results, you could most appropriately infer that the _____