LSAT PrepTest 79, Logical Reasoning II, Question 6 Explanation

LR Question 6 Explanation, by LSATHacks

QUESTION TEXT: Scientist: Laboratory animals have access to ample…

QUESTION TYPE: Necessary Assumption

CONCLUSION: The fact that lab animals get lots of food and little exercise can skew the results of scientific research on those animals.

REASONING: These studies assume that the animals are healthy.

ANALYSIS: This is one of those questions where you may already be assuming the correct answer without realizing it. If an argument seems obvious, ask yourself if you’re adding any additional assumptions without noticing. In this case, the assumption is that if an animal eats too much and doesn’t exercise, that animal will be unhealthy.

___________

This is actually an insane statement. Taken literally, it means that “restricted diet + plenty of exercise –> healthy”.
With no exceptions. So, if an animals gets….Cancer? No matter, the animal will be healthy if it gets exercise. Fatal stab wound? The animal will live, if given a restricted diet and exercise! You have to think literally on the LSAT.
Negation: 99.9% of lab animals are healthy when given a restricted diet and plenty of exercise. 0.01% are unhealthy due to preexisting disease and other factors.
CORRECT. The argument hinged on that fact that studies assume animals are healthy. If this answer isn’t true, then that assumption is valid and the argument falls apart.
Negation: There’s nothing unhealthy about giving animals ample food and little exercise.
So? This answer could be referring to pets. The question is whether such animals are unhealthy.
“Some” could refer to two studies out of 100,000. This answer isn’t significant. Negating it could mean moving from 2 to 0, which hardly makes a difference: either way most studies don’t consider living conditions.
Why would we care about variation? It doesn’t tell us whether an animal is health or not. If an animal eats 20% too much per day, without variation, they will become fat. If they eat 40% too little, without variation, they will starve. Lack of variation by itself tells us nothing.