Numbers and Percentages Review

The makers of the LSAT often prey upon several widely-held misconceptions:
Misconception #1: Increasing percentages automatically lead to
increasing numbers.
Misconception #2: Decreasing percentages automatically lead to
decreasing numbers.
Misconception #3: Increasing numbers automatically lead to increasing
percentages.
Misconception #4: Decreasing numbers automatically lead to decreasing
percentages.
Misconception #5: Large numbers automatically mean large
percentages, and small numbers automatically mean
small percentages.
Misconception #6: Large percentages automatically mean large
numbers, and small percentages automatically mean
small numbers.
Words that introduce numerical ideas:
Amount
Quantity
Sum
Total
Count
Tally
Words that introduce percentage ideas:
Percent
Proportion
Fraction
Ratio
Incidence
Likelihood
Probability
Segment
Share
Use the following general rules for Must Be True questions:
1. If the stimulus contains percentage or proportion information only, avoid
answers that contain hard numbers.
2. If the stimulus contains only numerical information, avoid answers that
contain percentage or proportion information.
3. If the stimulus contains both percentage and numerical information, any
answer choice that contains numbers, percentages, or both may be true.
Use the following general rules for Weaken and Strengthen questions:
To weaken or strengthen an argument containing numbers and
percentages, look carefully for information about the total amount(s)—
does the argument make an assumption based on one of the
misconceptions discussed earlier?
Market share is simply the portion of a market that a company controls. Market
share can be measured either in terms of revenues (sales) or units sold.
Regardless of the size of a market, total market share must always add up to
100%.

Assumption Question Type Review

An assumption is simply an unstated premise of the argument; that is, an
integral component of the argument that the author takes for granted and leaves
unsaid.
The relationship between the conclusion and the assumption can be described
as:
Conclusion Valid Assumption True
Hence, the answer you select as correct must contain a statement that the author
relies upon and is fully committed to in the argument.
Assumption question stems typically contain the following features:
1. The stem uses the word “assumption” or “presupposition” or some
variation.
2. The stem does not use the word “if” or another sufficient condition
indicator.
On the LSAT, assumptions play one of two roles: the Supporter or the
Defender:
Supporter Assumption: These assumptions link together new or rogue
elements in the stimulus or fill logical gaps in the
argument.
Defender Assumption: These assumptions contain statements that
eliminate ideas or assertions that would
undermine the conclusion. In this sense, they
“defend” the argument by showing that a
possible avenue of attack has been eliminated
(assumed not to exist).
Use the Assumption Negation Technique to decide between Contenders or to
confirm that the answer you have chosen is correct. The purpose of this
technique is to take an Assumption question, which is generally more difficult,
and turn it into a Weaken question. This technique can only be used on
Assumption questions. Take the following step to apply this technique:
1. Logically negate the answer choices under consideration.
2. The negated answer choice that attacks the argument will be the correct
answer.
Negating a statement consists of creating the logical opposite of the statement.
The logical opposite is the statement that denies the truth of the original
statement, and a logical opposite is different than the polar opposite.
To negate a conditional statement you must show that the necessary condition is
not in fact necessary.
The assumption underlying conditional reasoning is that the necessary condition
must occur in order for the sufficient condition to occur. Thus, the author
always assumes that any statement that challenges the truth of the relationship is
false. If you see a conditional conclusion and then are asked an Assumption
question, immediately look for an answer that confirms that the necessary
condition is truly necessary or one that eliminates possible alternatives to the
necessary condition.
Assumption answer choices tend to work exactly like Strengthen answer
choices in arguments with causal reasoning. Because the author always assumes
the stated cause is the only cause, the correct answer to an Assumption question
will normally fit one of the following categories:
A. Eliminates any alternate cause for the stated effect
B. Shows that when the cause occurs, the effect occurs
C. Shows that when the cause does not occur, the effect does not occur
D. Eliminates the possibility that the stated relationship is reversed
E. Shows that the data used to make the causal statement are accurate, or
eliminates possible problems with the data

Justify the Conclusion Question Type Review

Justify the Conclusion questions require you to select an answer choice that
logically proves the conclusion of the argument.
To solve this type of question, apply the Justify FormulaTM:
Premises + Answer choice = Conclusion
Justify questions all conform to the following relationship:
Answer choice(Correct)--------------> Conclusion(Valid)
Most Justify the Conclusion question stems typically contain some of the
following three features:
1. The stem uses the word “if” or another sufficient condition indicator.
2. The stem uses the phrase “allows the conclusion to be properly
drawn” or “enables the conclusion to be properly drawn.”
3. The stem does not lessen the degree of justification.
Most Justify stimuli either use Conditional Reasoning or contain numbers and
percentages.
Because Justify the Conclusion questions can be characterized in formulaic
terms, you can often solve these questions using a mechanistic approach. This
approach requires you to reduce the stimulus to its component parts (a process
that occurs naturally as you identify premises and conclusions), and then
identify which elements appear in the conclusion but not the premises. The
following rules apply:
1. Any “new” element in the conclusion will appear in the correct answer.
2. Elements that are common to the conclusion and at least one premise, or
to two premises, normally do not appear in the correct answer.
3. Elements that appear in the premises but not the conclusion normally
appear in the correct answer.

Strengthen Question Type Review

Although you do not need to memorize the types of wrong answer choices
that appear in Strengthen questions, you must memorize the ways to
strengthen a causal argument.
Strengthen questions ask you to identify the answer choice that best supports
the argument.
Use the following points to effectively strengthen arguments:
1. Identify the conclusion—this is what you are trying to strengthen!
2. Personalize the argument.
3. Look for weaknesses or holes in the argument.
The same type of wrong answer traps appear in Strengthen as in Weaken
questions:
1. Opposite Answers.
2. Shell Game Answers.
3. Out of Scope Answers.
In Strengthen questions, supporting a cause and effect relationship almost
always consists of performing one of the following tasks:
A. Eliminate any alternate causes for the stated effect
B. Show that when the cause occurs, the effect occurs
C. Show that when the cause does not occur, the effect does not occur
D. Eliminate the possibility that the stated relationship is reversed
E. Show that the data used to make the causal statement is accurate, or
eliminate possible problems with the data

Weaken Question Type Review

Weaken questions require you to select an answer choice that undermines the
author’s argument as decisively as possible. Keep these fundamental rules in
mind when you approach Weaken questions:
1. The stimulus will contain an argument.
2. Focus on the conclusion.
3. The information in the stimulus is suspect. There are often reasoning
errors present, and you must read the argument very carefully.
4. Weaken questions often yield strong prephrases.
5. The answer choices are accepted as given, even if they include
“new” information.
The conclusion is the part of the argument that is most likely to be attacked, but
the correct answer choice will not simply contradict the conclusion. Instead, the
correct answer will undermine the conclusion by showing that the conclusion
fails to account for some element or possibility. In this sense, the correct answer
often shows that the conclusion does not necessarily follow from the premises
even if the premises are true.
Several scenarios that can occur in LSAT Weaken question stimuli are easy to
recognize and attack:
1. Incomplete Information.
2. Improper Comparison.
3. Qualified Conclusion.
There are certain incorrect answer choices that appear frequently in Weaken
questions:
1. Opposite Answers.
2. Shell Game Answers.
3. Out of Scope Answers.
There is a simple rule for weakening a conditional conclusion:
To weaken a conditional conclusion, attack the necessary condition by
showing that the necessary condition does not need to occur in order for
the sufficient condition to occur.