I85PREP
⌘ K
NTS GAT Subject study materials
NTS GAT Subject study resources

NTS GAT Subject practice questions

One question at a time. Build your NTS GAT Subject understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Subject-Specific Content (discipline of candidate's choice)

In subject-specific GAT preparation, a candidate must select a discipline and answer questions that test depth of knowledge in that field. Which statement best describes the purpose of the GAT Subject assessment?

  1. It certifies professional licensure to practise independently in that discipline
  2. It measures advanced subject mastery and analytical reasoning within a chosen discipline Correct answer.
  3. It ranks candidates against each other on a national merit list for admissions
  4. It verifies undergraduate coursework completion in the chosen field

Explanation

The GAT Subject is a graduate-level aptitude test that probes how well a candidate can reason with advanced concepts inside one selected discipline rather than certify practice rights or verify transcripts. It emphasizes conceptual command and analytical application, not licensing or coursework records.

Question 2Subject-Specific Content (discipline of candidate's choice)

A researcher studying memory wants to test whether spaced repetition improves long-term retention compared with massed practice. Which design most directly isolates the effect of the spacing schedule?

  1. Correlating self-reported study habits with grade point average across a whole university
  2. Measuring retention in one group before and after a spaced-repetition workshop
  3. Randomly assigning participants to spaced or massed study while holding total study time and material constant Correct answer.
  4. Comparing exam scores of students who chose their own study schedule with those who did not

Explanation

An experimental design with random assignment and controlled total study time isolates spacing as the causal variable. Self-selection, single-group pre-post designs, and correlational surveys all leave confounds such as motivation or prior ability uncontrolled.

Question 3Subject-Specific Content (discipline of candidate's choice)

In economics, a government imposes a binding price ceiling below the equilibrium price of a good. Which outcome is predicted by standard supply-and-demand analysis?

  1. No change in quantity traded, because the ceiling only limits price
  2. A shortage, because quantity demanded exceeds quantity supplied Correct answer.
  3. A surplus, because quantity supplied exceeds quantity demanded
  4. An immediate shift of the demand curve to the right

Explanation

A binding ceiling holds price below equilibrium, so at that price consumers demand more than producers are willing to supply, creating excess demand. Price controls move quantity along the curves rather than shifting them, and a surplus arises only from a binding floor.

Question 4Subject-Specific Content (discipline of candidate's choice)

A patient with chronic kidney disease has a reduced glomerular filtration rate. Which consequence is most directly explained by the physiological role of the kidney?

  1. Increased retention of nitrogenous waste products such as urea in the blood Correct answer.
  2. Enhanced reabsorption of glucose leading to lower blood glucose
  3. Reduced blood pressure caused by excessive sodium excretion
  4. Increased production of red blood cells due to higher erythropoietin output

Explanation

The glomerulus filters nitrogenous wastes, so a falling filtration rate allows urea and creatinine to accumulate in plasma. Erythropoietin production typically falls in kidney disease, causing anemia rather than polycythemia, and impaired sodium handling tends to raise rather than lower blood pressure.

Question 5Subject-Specific Content (discipline of candidate's choice)

In a database course, a table is normalized to third normal form (3NF). Which condition is guaranteed by 3NF but not by second normal form?

  1. Every non-key attribute depends on the whole primary key
  2. All foreign keys reference tables in the same schema
  3. No non-key attribute is transitively dependent on the primary key Correct answer.
  4. Every table has a single-attribute surrogate primary key

Explanation

Third normal form removes transitive dependencies, in which a non-key attribute depends on another non-key attribute rather than directly on the key. Eliminating partial dependencies on part of a composite key is the achievement of 2NF, so that property alone does not distinguish 3NF.

Question 6Subject-Specific Content (discipline of candidate's choice)

A historian argues that the printing press accelerated the spread of Reformation ideas across Europe. Which type of evidence would most directly support this causal claim?

  1. A modern textbook summarizing the theology of the Reformation
  2. Portraits of leading reformers painted by contemporary artists
  3. A census showing urban population growth in the sixteenth century
  4. Records of the number of pamphlets printed and their distribution networks in reformist cities Correct answer.

Explanation

Quantitative printing and distribution records link the technology directly to the circulation of reformist texts, which is the mechanism the claim asserts. Population figures, portraits, and modern summaries do not trace the movement of printed ideas.

Question 7Subject-Specific Content (discipline of candidate's choice)

In organic chemistry, which functional group is characterized by a carbon doubly bonded to oxygen and singly bonded to two other carbon groups?

  1. Ketone Correct answer.
  2. Carboxylic acid
  3. Ester
  4. Aldehyde

Explanation

A ketone has a carbonyl carbon bonded to two carbon substituents, whereas an aldehyde has at least one hydrogen on the carbonyl carbon. Carboxylic acids and esters both contain an additional oxygen bonded to the carbonyl carbon.

Question 8Subject-Specific Content (discipline of candidate's choice)

A candidate answers 60 of 80 subject questions correctly. What percentage of the questions did the candidate answer correctly?

  1. 80%
  2. 75% Correct answer.
  3. 72%
  4. 70%

Explanation

The percentage is found by dividing the correct count by the total and multiplying by 100: 60 divided by 80 equals 0.75, or 75 percent. This is straightforward proportional reasoning that appears in quantitative sections of subject aptitude tests.

Question 9Subject-Specific Content (discipline of candidate's choice)

In statistics, a researcher reports a p-value of 0.03 for a difference between two groups at the conventional 0.05 significance level. Which interpretation is correct?

  1. There is a 97 percent probability that the alternative hypothesis is true
  2. The result is statistically significant, so the null hypothesis is rejected at the 0.05 level Correct answer.
  3. There is a 3 percent probability that the null hypothesis is true
  4. The effect size is necessarily large because the p-value is small

Explanation

A p-value below the chosen alpha leads to rejection of the null hypothesis, so the finding is declared statistically significant. The p-value is the probability of data this extreme given the null, not the probability that the null or the alternative is true, and it says nothing directly about effect magnitude.

Question 10Subject-Specific Content (discipline of candidate's choice)

In constitutional law, the doctrine of judicial review refers to the power of courts to do which of the following?

  1. Appoint judges to vacant judicial seats
  2. Override a presidential veto by a two-thirds vote
  3. Amend the constitution when it becomes outdated
  4. Review the constitutionality of legislative and executive acts Correct answer.

Explanation

Judicial review is the authority of courts to assess whether statutes and executive actions conform to the constitution and to invalidate those that do not. Appointment, amendment, and veto override belong to other branches or to the legislature respectively.

Question 11Subject-Specific Content (discipline of candidate's choice)

A literary critic examines how a narrator's unreliability shapes the reader's understanding of events in a novel. Which critical approach does this most closely exemplify?

  1. Marxist criticism focused on class conflict
  2. New Criticism treating the text as an autonomous verbal artifact
  3. Narratological analysis of point of view and discourse Correct answer.
  4. Biographical criticism linking the work to the author's life

Explanation

Narratology studies the structures of narration, including voice, focalization, and reliability, which is precisely the object of the critic's inquiry. Marxist, biographical, and formalist approaches organize interpretation around class, author biography, or intrinsic textual unity instead.

Question 12Subject-Specific Content (discipline of candidate's choice)

In computer science, which data structure provides average constant-time insertion and lookup by key while allowing key-value pairs to be stored?

  1. Balanced binary search tree
  2. Linked list
  3. Sorted array
  4. Hash table Correct answer.

Explanation

A hash table maps keys to buckets through a hash function, giving average constant-time insertion and lookup when the load factor is controlled. A balanced tree gives logarithmic time, a sorted array gives logarithmic search but costly insertion, and a linked list gives linear search.

Question 13Subject-Specific Content (discipline of candidate's choice)

A company's revenue rises from 200 million to 250 million over one year. What is the percentage increase in revenue?

  1. 25% Correct answer.
  2. 50%
  3. 30%
  4. 20%

Explanation

Percentage increase equals the change divided by the original value, multiplied by 100: 50 divided by 200 equals 0.25, or 25 percent. Dividing by the new value instead of the original produces the common error of 20 percent.

Question 14Subject-Specific Content (discipline of candidate's choice)

In genetics, a cross between two heterozygous individuals for a single gene with complete dominance yields offspring in which ratio of phenotypes?

  1. 3:1 Correct answer.
  2. 1:2:1
  3. 1:1
  4. 9:3:3:1

Explanation

A monohybrid cross of two heterozygotes gives a genotypic ratio of 1:2:1, which collapses to a 3:1 phenotypic ratio when the heterozygote is indistinguishable from the dominant homozygote. The 9:3:3:1 ratio arises only in a dihybrid cross of two independently assorting genes.

Question 15Subject-Specific Content (discipline of candidate's choice)

An engineer designs a bridge and must choose a material for a load-bearing beam. Which material property most directly resists elastic deformation under tensile stress?

  1. Poisson's ratio
  2. Young's modulus Correct answer.
  3. Thermal conductivity
  4. Ductility

Explanation

Young's modulus measures stiffness, the ratio of stress to elastic strain, so a higher value means less elastic deformation for a given stress. Ductility concerns plastic deformation before fracture, conductivity concerns heat flow, and Poisson's ratio describes lateral contraction relative to axial extension.

Question 16Subject-Specific Content (discipline of candidate's choice)

In international relations, the concept of balance of power suggests that stability is most likely when which condition holds?

  1. All states dissolve their armed forces under a collective treaty
  2. Economic sanctions are applied uniformly to every state in a region
  3. Power is distributed so that no single state or coalition can dominate Correct answer.
  4. One state possesses overwhelming military superiority over all others

Explanation

Balance-of-power theory holds that peace is preserved when capabilities are distributed so that no actor can achieve hegemony, whether through internal balancing or alliances. A single dominant power describes hegemony, and universal disarmament or blanket sanctions are not the mechanism the theory identifies.

Question 17Subject-Specific Content (discipline of candidate's choice)

A physician prescribes a drug that inhibits the enzyme responsible for converting angiotensin I to angiotensin II. Which physiological effect is expected?

  1. Elevated angiotensin II concentration in plasma
  2. Increased renin release from the macula densa
  3. Increased sodium reabsorption in the distal tubule
  4. Vasodilation with reduced aldosterone secretion Correct answer.

Explanation

Blocking the converting enzyme lowers angiotensin II, so arterioles dilate and aldosterone falls, reducing sodium retention and blood pressure. Angiotensin II cannot rise when its synthesis is inhibited, and renin typically increases as a compensatory response rather than being suppressed.

Question 18Subject-Specific Content (discipline of candidate's choice)

In a philosophy of science course, the problem of underdetermination of theory by evidence asserts which of the following?

  1. Theories are chosen purely by aesthetic preference
  2. Competing theories may be equally consistent with all available evidence Correct answer.
  3. Scientific theories can never be tested against observation
  4. Observational data are always theory-neutral and decisive

Explanation

Underdetermination holds that the same body of evidence can support more than one incompatible theory, so evidence alone may not force a unique choice. It does not claim that testing is impossible, nor that data are theory-neutral, nor that choice is purely aesthetic.

Question 19Subject-Specific Content (discipline of candidate's choice)

A firm operating in a perfectly competitive market is in long-run equilibrium. Which condition characterizes this state?

  1. Firms restrict output collectively to raise the market price
  2. Marginal revenue exceeds price because of product differentiation
  3. Price exceeds marginal cost, yielding persistent economic profit
  4. Price equals minimum average total cost and economic profit is zero Correct answer.

Explanation

In long-run competitive equilibrium, entry and exit drive price to the minimum of average total cost, so firms earn only normal profit and economic profit is zero. Persistent profit would attract entry, and product differentiation or collusion contradicts the assumptions of perfect competition.

Question 20Subject-Specific Content (discipline of candidate's choice)

In linguistics, the distinction between phonetics and phonology is best captured by which statement?

  1. Phonetics studies physical speech sounds, while phonology studies how sounds function in a language's system Correct answer.
  2. Phonetics applies only to vowels, while phonology applies only to consonants
  3. Phonetics studies written symbols, while phonology studies spoken words
  4. Phonetics concerns syntax, while phonology concerns semantics

Explanation

Phonetics examines the articulation, acoustics, and perception of speech sounds, whereas phonology analyzes how those sounds pattern and contrast within a particular language. Neither discipline is defined by writing systems, by syntax or semantics, or by a vowel-consonant split.

Question 21Subject-Specific Content (discipline of candidate's choice)

A researcher conducts a study with a sample of 400 and reports a 95 percent confidence interval of 10.0 to 14.0 for a mean. Which statement is the correct interpretation of this interval?

  1. Ninety-five percent of the population values fall between 10.0 and 14.0
  2. There is a 95 percent chance that the sample mean lies between 10.0 and 14.0
  3. If the study were repeated many times, about 95 percent of intervals constructed this way would contain the true mean Correct answer.
  4. The true mean is guaranteed to lie between 10.0 and 14.0

Explanation

Frequentist confidence intervals are interpreted through repeated sampling: approximately 95 percent of intervals built by this procedure capture the true parameter. The interval does not describe the probability of the sample mean, the spread of individual population values, or a guarantee about the parameter.

Question 22Subject-Specific Content (discipline of candidate's choice)

In accounting, a company purchases equipment for cash. How does this transaction affect the balance sheet?

  1. Total assets decrease and owner's equity decreases
  2. Total assets increase and total liabilities increase
  3. Total assets remain unchanged because one asset is exchanged for another Correct answer.
  4. Total assets increase and owner's equity increases

Explanation

Purchasing equipment for cash swaps one asset for another, so equipment rises while cash falls by the same amount and total assets are unchanged. The accounting equation stays balanced without affecting liabilities or equity, since no borrowing or revenue is involved.

Question 23Subject-Specific Content (discipline of candidate's choice)

In cell biology, the sodium-potassium pump moves ions across the plasma membrane. Which description correctly states its transport mechanism?

  1. It moves sodium and potassium down their gradients without energy input
  2. It moves two sodium ions out and three potassium ions in, using ATP
  3. It moves three sodium ions out and two potassium ions in, using ATP Correct answer.
  4. It moves three sodium ions in and two potassium ions out, using ATP

Explanation

The pump is an ATP-driven antiporter that exports three sodium ions and imports two potassium ions per cycle, generating a net outward current and maintaining the resting membrane potential. The stoichiometry and direction of the other options are incorrect, and the process is active rather than passive.

Question 24Subject-Specific Content (discipline of candidate's choice)

A software team must ensure that a function behaves correctly for valid inputs and rejects invalid ones. Which testing approach is most appropriate for verifying that invalid inputs are handled gracefully?

  1. Load testing with maximum concurrent users
  2. Negative testing using invalid or malformed inputs Correct answer.
  3. Regression testing of previously fixed defects
  4. Boundary value analysis applied only to valid partitions

Explanation

Negative testing deliberately supplies invalid, malformed, or out-of-range inputs to confirm that the system rejects or handles them gracefully. Boundary analysis of valid partitions, load testing, and regression testing target different risks and do not focus on invalid-input handling.

Question 25Subject-Specific Content (discipline of candidate's choice)

In a study of reaction times, the distribution is strongly right-skewed with a few very slow responses. Which measure of central tendency best represents the typical response time?

  1. Range
  2. Median Correct answer.
  3. Standard deviation
  4. Mean

Explanation

The median is resistant to extreme values because it depends on rank position rather than magnitude, so it better represents a typical value in a skewed distribution. The mean is pulled toward the long tail, while range and standard deviation measure dispersion rather than central tendency.

Question 26Subject-Specific Content (discipline of candidate's choice)

In economics, the opportunity cost of attending a full-time graduate program is best described as which of the following?

  1. The total tuition and living expenses paid during the program
  2. The value of the best alternative forgone, such as earnings from a job taken instead of studying Correct answer.
  3. The sum of tuition plus the value of all leisure time spent on recreation
  4. The income earned after graduation minus the tuition paid

Explanation

Opportunity cost is the value of the next-best alternative given up when a choice is made, so it includes forgone earnings rather than only explicit payments. Tuition is an explicit (accounting) cost, not the whole opportunity cost. Adding leisure or post-graduation income confuses the concept with unrelated cash flows.

Question 27Subject-Specific Content (discipline of candidate's choice)

A market has many buyers and sellers, homogeneous products, free entry, and each firm is a price taker. Which market structure does this describe?

  1. Monopolistic competition
  2. Oligopoly
  3. Perfect competition Correct answer.
  4. Monopoly

Explanation

Perfect competition is defined by many small firms, identical products, perfect information, free entry and exit, and firms that must accept the market price. Monopolistic competition involves differentiated products, and oligopoly and monopoly involve market power that prevents price-taking.

Question 28Subject-Specific Content (discipline of candidate's choice)

A firm's total fixed cost is 500 and its total variable cost at 100 units of output is 1,500. What is the average total cost at that output level?

  1. 20 Correct answer.
  2. 1,500
  3. 15
  4. 5

Explanation

Total cost equals fixed cost plus variable cost, so 500 + 1,500 = 2,000. Average total cost divides total cost by output: 2,000 / 100 = 20 per unit. The other figures misapply the formula by omitting a cost component or dividing the wrong quantity.

Question 29Subject-Specific Content (discipline of candidate's choice)

When a government imposes a binding price ceiling below the equilibrium price, which outcome is predicted in a competitive market?

  1. An increase in total surplus because consumers pay less
  2. A shortage because quantity demanded exceeds quantity supplied Correct answer.
  3. No change because the ceiling does not affect transactions
  4. A surplus because quantity supplied exceeds quantity demanded

Explanation

A binding ceiling sits below equilibrium, so at that lower price quantity demanded rises and quantity supplied falls, producing excess demand (a shortage). Surpluses arise from binding price floors, not ceilings. Ceilings typically reduce total surplus by creating deadweight loss.

Question 30Subject-Specific Content (discipline of candidate's choice)

In a repeated game, two firms can sustain cooperation on a high price even though the one-shot game has a dominant incentive to undercut. Which mechanism best explains this outcome?

  1. Cooperation is possible only if both firms have identical cost structures
  2. The credible threat of future punishment makes cooperation a subgame-perfect strategy Correct answer.
  3. Randomizing strategies each period eliminates the incentive to defect
  4. The Nash equilibrium of the one-shot game automatically applies each period

Explanation

In repeated games, players can condition future actions on past behavior, so the threat of punishment (for example, a tit-for-tat or grim-trigger strategy) can make cooperation sustainable when the discount factor is high enough. Identical costs are not required, and randomization does not remove the defection incentive. The one-shot equilibrium logic changes once repetition creates future consequences.

Question 31Subject-Specific Content (discipline of candidate's choice)

A country's central bank raises the policy interest rate. According to standard macroeconomic transmission, which effect is most likely in the short run?

  1. The currency tends to depreciate, raising import prices
  2. Inflation expectations rise immediately because rates signal expansion
  3. Borrowing costs rise, reducing investment and interest-sensitive consumption Correct answer.
  4. Investment and consumption spending rise, increasing aggregate demand

Explanation

Higher policy rates raise the cost of borrowing, which typically reduces investment and interest-sensitive consumption, dampening aggregate demand. Higher rates usually attract capital and support currency appreciation, not depreciation. Tightening is intended to lower, not raise, inflation pressures.

Question 32Subject-Specific Content (discipline of candidate's choice)

Real GDP per capita is often preferred to nominal GDP when comparing living standards across countries over time because it does which of the following?

  1. Adjusts for price-level changes and population size Correct answer.
  2. Counts only goods traded in international markets
  3. Includes the value of unpaid household production
  4. Reflects the distribution of income within each country

Explanation

Using real rather than nominal GDP removes the effect of price changes, and dividing by population controls for country size, making cross-country and intertemporal comparisons more meaningful. It still excludes unpaid household work, ignores income distribution, and includes non-traded goods.

Question 33Subject-Specific Content (discipline of candidate's choice)

A quadratic function f(x) = ax^2 + bx + c has a = 2 and its vertex occurs at x = 3. What is the value of b?

  1. -12 Correct answer.
  2. -6
  3. 6
  4. 12

Explanation

The vertex of a parabola y = ax^2 + bx + c lies at x = -b/(2a). Setting -b/(2a) = 3 with a = 2 gives -b = 12, so b = -12. The other values come from dropping the negative sign or misapplying the factor of 2a.

Question 34Subject-Specific Content (discipline of candidate's choice)

A fair six-sided die is rolled twice. What is the probability that the sum of the two rolls equals 7?

  1. 1/12
  2. 1/36
  3. 1/6 Correct answer.
  4. 1/9

Explanation

There are 36 equally likely ordered outcomes. The sum 7 occurs in six of them: (1,6), (2,5), (3,4), (4,3), (5,2), (6,1). Thus the probability is 6/36 = 1/6. The other fractions miscount the favorable outcomes or total outcomes.

Question 35Subject-Specific Content (discipline of candidate's choice)

The sequence 3, 7, 11, 15, ... continues with a constant common difference. What is the 20th term of the sequence?

  1. 75
  2. 80
  3. 79 Correct answer.
  4. 83

Explanation

This is an arithmetic sequence with first term a = 3 and common difference d = 4. The nth term is a + (n-1)d, so the 20th term is 3 + 19(4) = 3 + 76 = 79. The other values result from using n instead of n-1 or misadding the difference.

Question 36Subject-Specific Content (discipline of candidate's choice)

In a right triangle, one acute angle measures 30 degrees and the side opposite it has length 5. What is the length of the hypotenuse?

  1. 5√2
  2. 2.5
  3. 5√3
  4. 10 Correct answer.

Explanation

The sine of an angle equals the opposite side over the hypotenuse, so sin 30 = 5/hypotenuse. Since sin 30 = 0.5, the hypotenuse equals 5/0.5 = 10. The other values correspond to other trigonometric ratios or to the 45-degree case.

Question 37Subject-Specific Content (discipline of candidate's choice)

A matrix A is 3 by 4 and matrix B is 4 by 2. Which statement about the product AB is correct?

  1. AB is defined and has dimensions 3 by 4
  2. AB is defined and has dimensions 4 by 4
  3. AB is defined and has dimensions 3 by 2 Correct answer.
  4. AB is undefined because the outer dimensions differ

Explanation

Matrix multiplication requires the number of columns of the first matrix to equal the number of rows of the second. Here 4 equals 4, so the product is defined, and its dimensions are the outer dimensions, 3 by 2. The other options misstate the dimension rule.

Question 38Subject-Specific Content (discipline of candidate's choice)

The function f(x) = x^3 - 3x has a local maximum and a local minimum. At which x-value does the local maximum occur?

  1. x = -1 Correct answer.
  2. x = 3
  3. x = 1
  4. x = 0

Explanation

The derivative is f'(x) = 3x^2 - 3, which vanishes at x = 1 and x = -1. The second derivative 6x is negative at x = -1, confirming a local maximum there. At x = 1 the second derivative is positive, indicating a local minimum.

Question 39Subject-Specific Content (discipline of candidate's choice)

A function f is continuous on the closed interval [a, b] and differentiable on (a, b). If f(a) = f(b), what does Rolle's theorem guarantee?

  1. There exists a point c where f''(c) = 0
  2. f is constant on the entire interval [a, b]
  3. There exists at least one point c in (a, b) where f'(c) = 0 Correct answer.
  4. f attains its maximum at an endpoint only

Explanation

Rolle's theorem states that under these hypotheses there is at least one interior point where the derivative equals zero. It does not require the function to be constant, nor does it assert anything about the second derivative. A continuous function on a closed interval attains extrema, but they need not be only at endpoints.

Question 40Subject-Specific Content (discipline of candidate's choice)

A researcher wants to test whether a new teaching method changes average scores, with no prior expectation about direction. Which pair of hypotheses is appropriate?

  1. H0: mean > 75; H1: mean < 75
  2. H0: mean = 75; H1: mean ≠ 75 Correct answer.
  3. H0: mean ≠ 75; H1: mean = 75
  4. H0: mean = 75; H1: mean > 75

Explanation

A two-sided test is appropriate when no directional expectation exists, so the alternative states that the mean differs from the value, using the inequality sign. The null always contains equality. Directional alternatives are reserved for one-sided tests with prior expectations, and the null never carries an inequality.

Question 41Subject-Specific Content (discipline of candidate's choice)

A study finds a correlation of 0.85 between hours of study and exam scores. Which interpretation is most defensible?

  1. The correlation proves that 85 percent of score variance is explained by study time
  2. There is a strong positive association, but causation cannot be inferred from correlation alone Correct answer.
  3. Because the correlation is high, the relationship must be linear and free of confounders
  4. Increased study time causes higher scores, as shown by the strong correlation

Explanation

Correlation measures the strength and direction of a linear association, not causation, so a strong positive value supports association only. The proportion of variance explained is the square of the correlation (about 0.72), not the correlation itself. High correlation does not rule out confounding or nonlinearity.

Question 42Subject-Specific Content (discipline of candidate's choice)

In a database, a table stores orders and another stores customers, and each order references exactly one customer. Which design correctly enforces this relationship?

  1. A composite primary key spanning both tables
  2. A foreign key in the customers table referencing the order primary key
  3. A check constraint on the customer name column
  4. A foreign key in the orders table referencing the customer primary key Correct answer.

Explanation

A one-to-many relationship from customers to orders is enforced by placing a foreign key in the many-side table (orders) that references the primary key of the one-side table (customers). Placing the key in the customers table would model the reverse cardinality incorrectly, and a check constraint on a name does not enforce referential integrity.

Question 43Subject-Specific Content (discipline of candidate's choice)

A recursive algorithm solves a problem of size n by dividing it into two halves, solving each, and combining results in linear time. Its recurrence is T(n) = 2T(n/2) + n. What is its asymptotic time complexity?

  1. O(n log n) Correct answer.
  2. O(n)
  3. O(n^2)
  4. O(log n)

Explanation

Applying the master theorem, a = 2, b = 2, and the combine cost is f(n) = n. Since n equals n^(log base 2 of 2) = n, the result falls in the balanced case, giving O(n log n). Linear and logarithmic bounds ignore the work done at each of the log n levels, and quadratic overstates the cost.

Question 44Subject-Specific Content (discipline of candidate's choice)

In a computer network, which protocol provides reliable, ordered delivery of a byte stream between hosts?

  1. User Datagram Protocol (UDP)
  2. Address Resolution Protocol (ARP)
  3. Transmission Control Protocol (TCP) Correct answer.
  4. Internet Protocol (IP)

Explanation

TCP establishes connections and uses acknowledgments, sequencing, and retransmission to provide reliable, ordered delivery. UDP is connectionless and unreliable, IP provides best-effort routing without guarantees, and ARP resolves IP addresses to link-layer addresses.

Question 45Subject-Specific Content (discipline of candidate's choice)

A program uses a stack to evaluate a postfix expression. Which operation is performed when an operator symbol is encountered?

  1. Pop one operand and replace the operator with it
  2. Pop two operands, apply the operator, and push the result Correct answer.
  3. Push the operator onto the stack for later use
  4. Clear the stack and restart the evaluation

Explanation

In postfix evaluation, operands are pushed as they are read, and each operator consumes the top two operands, computes the result, and pushes it back. The stack therefore holds intermediate values until the expression is exhausted. Pushing operators or clearing the stack would break the evaluation order.

Question 46Subject-Specific Content (discipline of candidate's choice)

In object-oriented design, which principle states that software entities should be open for extension but closed for modification?

  1. Interface segregation principle
  2. Liskov substitution principle
  3. Open-closed principle Correct answer.
  4. Single responsibility principle

Explanation

The open-closed principle holds that behavior should be extendable without altering existing source code, typically through abstraction and polymorphism. Single responsibility concerns a class having one reason to change, Liskov substitution concerns subtype substitutability, and interface segregation concerns keeping interfaces narrow.

Question 47Subject-Specific Content (discipline of candidate's choice)

A researcher wants to determine whether a new drug reduces blood pressure more than a placebo while controlling for baseline differences. Which design is most appropriate?

  1. A cross-sectional survey of patients at one clinic
  2. A case study of one patient's response to the drug
  3. A randomized controlled trial with a placebo group Correct answer.
  4. An observational cohort comparing patients who chose the drug with those who did not

Explanation

Random assignment to drug or placebo balances both measured and unmeasured confounders, supporting a causal comparison of the treatment effect. Surveys and case studies cannot establish causal effects, and self-selected cohorts introduce confounding by indication.

Question 48Subject-Specific Content (discipline of candidate's choice)

A study reports a 95 percent confidence interval for a mean difference of [0.5, 3.5]. Which conclusion is most appropriate?

  1. The effect size is large because the interval is entirely positive
  2. The true difference is certainly between 0.5 and 3.5
  3. Because the interval excludes zero, the difference is statistically significant at the 0.05 level Correct answer.
  4. The probability that the true difference lies in this interval is exactly 95 percent

Explanation

A confidence interval that excludes the null value of zero corresponds to rejecting the null at the 0.05 two-sided level. The interval does not guarantee that the parameter lies within it, and the frequentist interpretation concerns the procedure's long-run coverage, not the probability for a given interval. Width and sign alone do not establish a large effect size.

Question 49Subject-Specific Content (discipline of candidate's choice)

In a research report, a p-value of 0.04 is obtained for a treatment effect. Which statement best interprets this result under the null hypothesis?

  1. The treatment has a 96 percent chance of being effective in the population
  2. There is a 4 percent probability that the null hypothesis is true
  3. There is a 4 percent probability of observing data at least as extreme as these, assuming the null is true Correct answer.
  4. The result is practically important because p is below 0.05

Explanation

A p-value is the probability of obtaining a test statistic at least as extreme as the observed one, calculated assuming the null hypothesis is true. It is not the probability that the null is true, nor the probability of effectiveness. Statistical significance does not by itself establish practical importance.

Question 50Subject-Specific Content (discipline of candidate's choice)

In a research article, which section typically states the hypothesis, methods, results, and interpretation in condensed form?

  1. The acknowledgments
  2. The appendix
  3. The reference list
  4. The abstract Correct answer.

Explanation

The abstract is a concise summary placed at the start of an article that previews the purpose, methods, key results, and conclusions. Acknowledgments credit contributors and funders, references list cited sources, and appendices hold supplementary detail rather than the overview.