ATF Special Agent flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Analogy bridge

The precise relationship linking the first pair of words, such as part-to-whole, cause-to-effect, or worker-to-tool, which the answer pair must match exactly.

Contrast signal words

Words such as although, despite, however, and whereas that reverse a sentence's direction, so the blank must oppose rather than support the stated idea.

Main idea questions

The correct answer states what the entire passage is about and covers all paragraphs, while choices resting on a single detail or an overreach are wrong.

Scope error

An answer choice is incorrect when it claims more than the passage supports, usually signaled by absolute words such as all, never, always, must, or only.

Definition in context

The meaning a word carries as used in a particular sentence; test each option by substituting it back in and checking whether the sentence still makes sense.

Two-blank completion strategy

Solve the easier blank first, eliminate every choice that fails it, then verify that the surviving option also fits the second blank and the sentence's logic.

Antonym item rule

Select the choice opposite in meaning that matches the stem's part of speech, tone, and specific sense, rejecting opposites of a different definition of the word.

Common word roots

Prefixes and roots such as bene (good), mal (bad), cred (believe), loqu (speak), pug (fight), and ten (hold) reveal the meaning of unfamiliar words.

Percent change formula

Percent change equals new value minus old value, divided by the old value, times 100; the original amount is always the denominator.

Successive percent changes

Consecutive percent changes are combined by multiplying decimal factors, so a 20% rise followed by a 10% fall gives 1.2 × 0.9 = 1.08, an 8% net gain.

Average and sum relation

The average equals the sum divided by the count of terms, so the sum equals the average multiplied by the count; use this to recover a missing total.

Combined work rate

Rates add, times do not: if one worker needs a hours and another b hours, working together they finish the job in ab divided by (a + b) hours.

Average speed equal distances

When two equal distances are covered at speeds a and b, average speed is the harmonic mean 2ab divided by (a + b), not the simple average of a and b.

Mixture concentration rule

The amount of a substance equals concentration times volume; when solutions combine, add the substance amounts and divide by the new total volume.

Special right triangle ratios

A 45-45-90 triangle has sides in ratio 1:1:√2, and a 30-60-90 triangle has sides in ratio 1:√3:2 opposite the 30, 60, and 90 degree angles.

Compound interest formula

A = P(1 + r/n)^(nt), where P is principal, r the annual rate written as a decimal, n the compoundings per year, and t the number of years.

Contrapositive of conditional

From 'if P then Q' one may validly infer 'if not Q then not P'; the converse 'if Q then P' and the inverse are not logically valid.

Only if means necessary

The statement 'P only if Q' translates to P implies Q, making Q a necessary condition; it does not mean that Q by itself guarantees P.

Unless translation

'P unless Q' means 'if not Q then P'; unless introduces the condition whose absence is what forces the result P to occur.

Necessary versus sufficient

A sufficient condition guarantees the outcome, while a necessary condition must hold for the outcome but does not by itself guarantee that it occurs.

Negation test

To identify an argument's required assumption, negate each candidate statement; if the negation makes the argument collapse, that statement is the assumption.

Valid syllogism chain

All A are B combined with All B are C yields All A are C, while any chain containing a 'some' premise yields only a 'some' conclusion.

Strengthen or weaken method

Attack or support the link between evidence and conclusion by exposing an alternate cause, an unrepresentative sample, reversed causation, or a shift in terms.

Post hoc fallacy

Concluding that one event caused another merely because it happened first; sequence or correlation alone cannot establish a causal relationship.

Subject-verb agreement rule

The verb agrees with the true subject, ignoring intervening prepositional phrases; each, every, either, and neither are singular, while subjects joined by 'and' are plural.

Dangling modifier

An introductory descriptive phrase must modify the subject of the main clause; otherwise it dangles, as in 'Walking to the car, the rain began.'

Who versus whom

Use who for the subject of a clause and whom for a direct object or after a preposition, as in 'between you and me' or 'whom the agent questioned.'

Comma splice error

Joining two independent clauses with only a comma is an error; use a period, a semicolon, or a comma plus a coordinating conjunction instead.

Semicolon usage

A semicolon joins two closely related independent clauses with no conjunction after it; each side of the semicolon must be a complete sentence.

Parallel structure rule

Items in a list, comparison, or compound must share the same grammatical form, so nouns pair with nouns and infinitives pair with infinitives.

Fewer versus less

Fewer is used with countable items such as agents or cases, while less is used with uncountable amounts such as time, evidence, or money.

Its versus it's

Its is the possessive form meaning belonging to it, while it's is only the contraction of 'it is' or 'it has' and never shows possession.