Herman, the local dogcatcher, thinks that the dogs at the pound tend to bark less when they are fed expensive all-natural dog food than when they are fed a less expensive dog food that has preservatives. What is Herman's hypothesis?
1) The dogs at the pound bark less when they are fed expensive all-natural dog food.
2) The dogs at the pound bark less when they are fed a less expensive dog food that has preservatives.
3) The dogs at the pound bark the same amount regardless of the type of dog food they are fed.
4) The dogs at the pound bark more when they are fed expensive all-natural dog food.