The number of cavities in school-aged children and size of vocabulary are known to have a strong negative association. Toby concluded that the number of cavities causes a decrease in vocabulary. Is Toby's conclusion valid? Explain. Toby's conclusion is valid because association does imply causation. Toby's conclusion is not valid because causation does not imply association. Toby's conclusion is valid because causation does imply association. Toby's conclusion is not valid because association does not imply causation.