HEC HAT flashcards
HEC HAT · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Main Idea
- The central claim that the passage as a whole supports; the correct answer must cover every paragraph rather than a single supporting detail.
- Author's Tone
- The writer's attitude toward the subject, revealed by word choice; options range from neutral and objective to critical, satirical or admiring.
- Inference
- A statement not written directly in the passage but necessarily following from it; if the text allows it to be false, it is not a valid inference.
- Subject–Verb Agreement
- The verb must match the number of the real subject; prepositional phrases placed between subject and verb never change whether the verb is singular or plural.
- Dangling Modifier
- An introductory participial phrase must describe the subject of the main clause, otherwise it attaches to the wrong noun and the sentence becomes illogical.
- Parallelism
- Items joined by and, or, or in a series must share the same grammatical form, such as all nouns, all infinitives, or all clauses.
- Contrast Connectors
- Words such as although, though, despite and however signal opposition, so the second clause usually reverses the expectation created by the first.
- Vocabulary in Context
- Meaning is fixed by surrounding words rather than the dictionary's first sense; substitute each option into the sentence and test logic and tone.
- Percent Change
- The difference between new and original value divided by the original value, multiplied by 100; the denominator is always the starting figure.
- Successive Percentage Changes
- Two percentage changes multiply instead of adding: a 20% rise followed by a 20% fall gives 1.2 × 0.8 = 0.96, a net 4% decrease.
- Average Speed
- Total distance travelled divided by total time taken; averaging the speeds themselves is valid only when both time intervals are equal.
- Combined Work Rate
- If one worker finishes a job in a hours and another in b hours, together they complete 1/a + 1/b of it per hour.
- Compound Interest
- Amount equals P(1 + r/100)^n, and compound interest is that amount minus P; interest is earned on accumulated interest each period.
- Median versus Mean
- The median is the middle value of an ordered set and resists outliers; the mean is pulled up or down by extreme values.
- Mutually Exclusive Events
- Events that cannot occur together, so P(A or B) = P(A) + P(B); if they can overlap, subtract P(A and B).
- Standard Deviation
- A measure of spread around the mean; adding the same constant to every value shifts the mean but leaves the standard deviation unchanged.
- Contrapositive
- From 'if P then Q' you may validly infer 'if not Q then not P'; the converse 'if Q then P' is not valid.
- Sufficient Condition
- A condition that guarantees the outcome: whenever it holds the result must follow, although other conditions might also produce that result.
- Necessary Condition
- A condition without which the outcome cannot occur; the statement 'P only if Q' makes Q necessary and P sufficient.
- Assumption Negation Test
- Negate a candidate assumption; if the argument collapses the statement was required, and if it survives the candidate is not an assumption.
- Correlation versus Causation
- Two variables moving together does not prove one causes the other; an unobserved third factor or reverse causation may explain the link.
- Must Be True
- A statement fully supported by the given information; in 'except' questions four choices must be true and one cannot be.
- Sequencing Block Rule
- When a condition states that X is immediately before Y, treat XY as one fused unit occupying two consecutive positions in the arrangement.
- Weaken the Argument
- The answer attacks the link between evidence and conclusion, often by offering an alternative explanation or showing the evidence is unrepresentative.
- Price Elasticity of Demand
- Demand is elastic when the percentage change in quantity exceeds the percentage change in price, so cutting price raises total revenue.
- Net Present Value
- Future cash flows discounted at the cost of capital minus the initial outlay; a positive NPV means the project should be accepted.
- Accounting Equation
- Assets equal liabilities plus owners' equity; every transaction preserves this balance, which is why it is called the balance sheet identity.
- Big-O Notation
- Describes how running time grows with input size: binary search is O(log n), merge sort O(n log n), and average hash lookup O(1).
- Mitosis versus Meiosis
- Mitosis produces two genetically identical diploid cells for growth and repair; meiosis produces four genetically varied haploid gametes for sexual reproduction.
- Mole
- One mole contains 6.022 × 10²³ particles, Avogadro's number, and equals the substance's molar mass expressed in grams.
- Type I Error
- Rejecting a null hypothesis that is actually true, a false positive; its probability equals the significance level alpha, commonly set at 0.05.
- Newton's Second Law
- Force equals mass times acceleration, F = ma; acceleration points in the direction of the net force and is inversely proportional to mass.