Complete Question Explanation

As with all questions, you must identify the conclusion of the argument.

The conclusion states that if you buy a Bolter’s power hedge trimmer, you

know the trimmer is safe. In the question stem, we are asked to evaluate

the truth of this conclusion. Each answer choice is then posed in the form

of a question. The answer choice that is correct will contain the question

that, when answered, will reveal whether the conclusion is strong or weak.

In order to understand the application of the Variance Test, we will look at

each answer choice in succession and thus we will not perform an initial

analysis of the argument (on the LSAT we would analyze the stimulus

closely). Also note that on the test we would not apply the Variance Test

to each answer choice, only to the Contenders. For teaching purposes, we

will apply the Variance Test to each answer in an effort to give you the best

possible understanding of how the technique works.

Answer choice (A) asks if National Laboratories has performed tests on

other machines from Bolter Industries. To apply the Variance Test, we

should supply different and opposing answers to the question posed by the

answer choice. First, try the answer “No.” With this answer, would the fact

that National Laboratories did not perform safety tests on other Bolter’s

machines affect the safety of the Bolter’s hedge trimmer? No—this does

not help us evaluate the safety of the hedge trimmer. What if the answer

was “Yes” ? Would the fact that National Laboratories performed safety

tests on other Bolters machines affect the safety of the Bolter’s hedge

trimmer? Not at all. So, regardless of how we respond to the question

posed in answer choice (A), our view of the conclusion is the same—we

do not know whether the claim that the hedge trimmer is safe is good

or bad. According to the Variance Test, if the answer is correct, then

supplying opposite answers should yield different views of the conclusion.

Since our assessment of the conclusion did not change, the Variance Test

tells us that this answer is incorrect.

The question in answer choice (B) is, “How important to the average

buyer of a power hedge trimmer is safety of operation?” Again, apply the

Variance Test and supply opposite answers to the question in the answer

choice. In this case, try “Very Important” and “Not Important.” If safety

of operation is very important to a buyer of hedge trimmers, would that

affect whether the Bolter’s hedge trimmer itself is safe? No. Let’s look at

the opposite side: if safety of operation is not important at all to a buyer

of hedge trimmers, would that affect whether the Bolter’s hedge trimmer

itself is safe? No. Because our view of the validity of the conclusion does

not change when we consider different responses to the question posed

in answer choice (B), the Variance Test tells us that answer choice (B) is

incorrect.

The question in answer choice (C) is, what were the results of the tests of

Bolter’s hedge trimmer? Using the Variance Test, supply one response that

says, “Bolter’s hedge trimmer failed the safety test.” If this is true, then

the conclusion is unquestionably weakened. Now supply a response that

says, “Bolter’s hedge trimmer passed the safety test.” If this is true, then

the conclusion is strengthened. So, depending on the answer supplied to

the question posed in answer choice (C), our view of the validity of the

argument changes: sometimes we view the conclusion as stronger and

other times as weaker.

the argument: the author simply assumed that being tested means safety is

assured. Nowhere in the argument did the author mention that the hedge

trimmer passed the tests, and the Variance Test reveals this flaw.

In answer choice (D), “Yes” and “No” responses do not change our view

of the argument, and answer choice (D) is incorrect.

In answer choice (E), “Yes” and “No” responses do not change our view

of the argument, and answer choice (E) is incorrect.

**Evaluate the Argument. The correct answer choice is (C).**

As with all questions, you must identify the conclusion of the argument.

The conclusion states that if you buy a Bolter’s power hedge trimmer, you

know the trimmer is safe. In the question stem, we are asked to evaluate

the truth of this conclusion. Each answer choice is then posed in the form

of a question. The answer choice that is correct will contain the question

that, when answered, will reveal whether the conclusion is strong or weak.

In order to understand the application of the Variance Test, we will look at

each answer choice in succession and thus we will not perform an initial

analysis of the argument (on the LSAT we would analyze the stimulus

closely). Also note that on the test we would not apply the Variance Test

to each answer choice, only to the Contenders. For teaching purposes, we

will apply the Variance Test to each answer in an effort to give you the best

possible understanding of how the technique works.

Answer choice (A) asks if National Laboratories has performed tests on

other machines from Bolter Industries. To apply the Variance Test, we

should supply different and opposing answers to the question posed by the

answer choice. First, try the answer “No.” With this answer, would the fact

that National Laboratories did not perform safety tests on other Bolter’s

machines affect the safety of the Bolter’s hedge trimmer? No—this does

not help us evaluate the safety of the hedge trimmer. What if the answer

was “Yes” ? Would the fact that National Laboratories performed safety

tests on other Bolters machines affect the safety of the Bolter’s hedge

trimmer? Not at all. So, regardless of how we respond to the question

posed in answer choice (A), our view of the conclusion is the same—we

do not know whether the claim that the hedge trimmer is safe is good

or bad. According to the Variance Test, if the answer is correct, then

supplying opposite answers should yield different views of the conclusion.

Since our assessment of the conclusion did not change, the Variance Test

tells us that this answer is incorrect.

The question in answer choice (B) is, “How important to the average

buyer of a power hedge trimmer is safety of operation?” Again, apply the

Variance Test and supply opposite answers to the question in the answer

choice. In this case, try “Very Important” and “Not Important.” If safety

of operation is very important to a buyer of hedge trimmers, would that

affect whether the Bolter’s hedge trimmer itself is safe? No. Let’s look at

the opposite side: if safety of operation is not important at all to a buyer

of hedge trimmers, would that affect whether the Bolter’s hedge trimmer

itself is safe? No. Because our view of the validity of the conclusion does

not change when we consider different responses to the question posed

in answer choice (B), the Variance Test tells us that answer choice (B) is

incorrect.

The question in answer choice (C) is, what were the results of the tests of

Bolter’s hedge trimmer? Using the Variance Test, supply one response that

says, “Bolter’s hedge trimmer failed the safety test.” If this is true, then

the conclusion is unquestionably weakened. Now supply a response that

says, “Bolter’s hedge trimmer passed the safety test.” If this is true, then

the conclusion is strengthened. So, depending on the answer supplied to

the question posed in answer choice (C), our view of the validity of the

argument changes: sometimes we view the conclusion as stronger and

other times as weaker.

**Therefore, according to the Variance Test, this is**

the correct answer.In this instance, the Variance Test reveals the flaw inthe correct answer.

the argument: the author simply assumed that being tested means safety is

assured. Nowhere in the argument did the author mention that the hedge

trimmer passed the tests, and the Variance Test reveals this flaw.

In answer choice (D), “Yes” and “No” responses do not change our view

of the argument, and answer choice (D) is incorrect.

In answer choice (E), “Yes” and “No” responses do not change our view

of the argument, and answer choice (E) is incorrect.