Conclusion: We can dismiss the widely held suspicion that sugar consumption often exacerbates hyperactivity in children with attention deficit disorder.
Premise: A scientific study of the effects of three common sugars on children who have ADD, along with experimental groups each receiving a type of a sugar and a control group receiving a sugar substitute showed no statistically significant difference between the groups in thinking or behavior.
So, let's say for the sake of the argument that all the children started at a hyperactivity level (purely made up for this explanation) of 5. If all the groups showed no statistically significant difference between the groups in thinking or behavior once they were given their respective substance, that could merely mean they were all increased at the same amount.
So, if answer choice (C) were true, and the consumption of the sugar substitute does exacerbate symptoms of hyperactivity, i.e. it raised the level of hyperactivity to 100, then according to the argument, all the other groups also raised their hyperactivity level to 100, i.e. there was no statistically significant difference between the groups.
Therefore, all the groups' hyperactivity level could have heightened, meaning both that sugar does in fact exacerbate hyperactivity in children with ADD and that, since sugar substitutes exacerbate the symptoms of hyperactivity, all the children behaved the same in their heightened level of hyperactivity.
Thus, answer choice (C) would weaken the argument since it would no longer necessarily lead to dismissing the widely held suspicion that sugar consumption often exacerbates hyperactivity in children with ADD.
Hope that clears things up! Please let us know if you have any other questions.
