Red imported fire ants are an ant species native to South America, but were introduced into the US in the 1950s. As their name suggests, their primary mode of defense against predators is to sting, and when they do so, they inject a toxin under the skin, leaving a very painful bite. It is not known whether ants are always producing the toxin they use in their sting, or if they only produce toxin in the presence of predators. Researchers collected the data below by measuring toxin concentration in many individual ants before and immediately following an attack by a nest predator (anteater). Error bars are +/- 2SE. What should they conclude?