LSAT Explanation PT 39, S4, Q4: Among North American school-age children, there

LSAT Question Stem

The argument requires the assumption that 

Logical Reasoning Question Type

This is a Necessary Assumption question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

First, let's analyze the argument in the passage. The argument has the following structure:

Premise: Among North American school-age children, there is a strong positive correlation between obesity and the amount of television watched.

Conclusion: With the arrival of interactive television, obesity among North American school-age children will increase.

The argument is making a prediction about the future based on the observed correlation between obesity and television watching. To make this more understandable, think of it like this: if we observe that people who eat more ice cream tend to gain more weight, we might predict that if a new, more delicious ice cream is introduced, people will gain even more weight.

Now, let's come up with an "Evaluate" question for this argument. A good question would be: "Will North American school-age children watch more television with the arrival of interactive television?"

The question type of this problem is Necessary Assumption, which means we need to find the assumption that must be true for the argument to hold.

Answer choice explanations:

a) A sedentary lifestyle is among the most important causes of childhood obesity.

This answer choice is not necessary for the argument. The argument is based on the correlation between obesity and television watching, not the overall causes of childhood obesity. It's possible that other factors contribute to obesity, but this doesn't affect the argument's conclusion.

b) Obesity among North American school-age children increased as cable television became widely available.

This answer choice is not necessary for the argument either. It may strengthen the argument by providing an example of how a new form of television increased obesity, but it's not required for the argument to be valid. The argument is based on the correlation between obesity and television watching, not the history of cable television.

c) Genetics makes no significant contribution to obesity.

This answer choice is also not necessary for the argument. The argument is based on the correlation between obesity and television watching, not the factors that contribute to obesity. It's possible that genetics plays a role in obesity, but this doesn't affect the conclusion that interactive television could lead to increased obesity.

d) North American school-age children will increase their television viewing with the arrival of interactive television.

This is the correct answer. The argument assumes that children will watch more television with the arrival of interactive television. If this assumption is not true, then the argument's conclusion doesn't hold. For example, if children don't watch more television with the arrival of interactive television, then there's no reason to believe that obesity will increase.

e) Within a decade of its introduction, interactive television will be almost universally available.

This answer choice is not necessary for the argument. The argument doesn't rely on the timeline or availability of interactive television. It's possible that interactive television doesn't become universally available or takes longer than a decade to do so, but this doesn't affect the argument's conclusion that interactive television could lead to increased obesity among North American school-age children.