The data shows that mouse color determines the frequency of predator attack, with predators readily attacking a mouse with a color that contrasts with the soil and is, therefore, easy to spot. They much more readily attack mice which have a color that doesn't blend into the soil. This supports the hypothesis that color is adaptive in this case.
Work Step by Step
To understand the graph, notice how the shorter bar in each case is for mice the same color as the soil (sandy soil in one case), which implies that predators don't notice the mice as easily because of their color. This works no matter the soil color, and fewer attacks would mean better survival and reproduction. Therefore, color is adaptive for these mice.