A recent poll of a large number of households found that 47 percent of those with a cat had at least one person with a university degree, while 38 percent of households with a dog had at least one person with a university degree.
Conclusion
People with degrees are more likely to live in a house with a cat than one with a dog.
Evidence
47% of houses with cats have someone with a degree. 38% of houses with dogs have someone with a degree.
Evaluate
The statistics presented in the evidence aren't very useful when it comes to ascertaining what the conclusion is talking about.
The conclusion wants to know whether there are more people with degrees living in a cat house or a dog house. (Houses with both don't really matter, because they "cancel each other out". If they have both a cat and a dog, then they won't affect the conclusion in either direction)
Does the evidence tell us whether there are more people with degrees living in a cat house or a dog house?
No, it just tells us that cat houses are more likely to have a college grad in them than are dog houses. That doesn't mean, however, that there are more college grads living in cat houses than in dog houses, because there could be 100 cat houses and 10,000 dog houses.
Goal
There are a lot of different ways to describe the problem here, but essentially the statistics presented don't allow us to make any judgment on the conclusion.
The premises are about Percent's whereas the conclusion comes down to a raw number comparison. It's expressed in "most likely" language, but the way you would decide whether people with degrees are more likely to live in a cat house vs. a dog house would simply be to ask, ?
The author's reasoning is that 47% is bigger than 38%, so there must be more people with degrees in cat houses than in dog houses, but those percentages are taken of different totals (47% of cat houses vs. 38% of dog houses), so they're not possible to directly compare.