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Test scope, conditional claims and causal arguments while judging three options independently.
Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.
Select all supported judgments about an unfamiliar argument without confusing possibility, necessity, sufficiency or causation.
All is stronger than some, must is stronger than may, and a statement about a whole population is stronger than one about a sampled subgroup. If a passage establishes at least one case, it does not necessarily establish most cases. A claim can be false as a universal rule while true for many examples. Review the reading-structure lesson for author versus reported voice, and formal logic for more sustained work on conditional relationships and valid inference.
| Term | What it means |
|---|---|
| Necessary condition | A condition required for another event or claim, without necessarily guaranteeing it. |
| Sufficient condition | A condition that guarantees another event or claim under the stated rule. |
| Confounder | A differing factor that can offer an alternative explanation for an observed relationship. |
| Counterexample | A case satisfying the premises but violating the proposed conclusion. |
A passage may state evidence and ask you to draw a conclusion, or present a conclusion and ask what supports, weakens or underlies it. These tasks use related reasoning but different standards. An inference answer must follow from the supplied information at the requested strength. A strengthening answer need only improve support for the argument; it need not prove the conclusion. An assumption is something the reasoning relies on, not simply another fact that would be helpful.
Three-option reading questions require evaluating each candidate separately. One, two or all three can be correct. Selecting one true statement is insufficient if another is also correct, and selecting an unsupported extra statement loses item credit. Do not search for a pattern in the number of correct answers. Apply the task's standard to each option and submit the exact set it warrants.
Another way: steps
Identify the task and conclusion; map the supporting evidence; locate the inferential gap; test each option independently; preserve the requested strength.
If the question asks what follows, treat the supplied statements as premises and reject claims requiring additional facts. If it asks what would strengthen, accept the option's proposed new information for the purpose of evaluating its effect. An option can be useful hypothetical evidence without already being stated in the passage. If it asks what is compatible, the test is whether a claim can coexist with the passage, which is weaker than whether it must follow. Mixing these standards makes plausible distractors appear correct for the wrong reason.
All finalists submitted portfolios means being a finalist is sufficient to establish portfolio submission, while portfolio submission is necessary for being a finalist. It does not mean everyone who submitted became a finalist. The valid contrapositive is that a person who did not submit was not a finalist. To test the invalid converse, imagine a portfolio submitter rejected before the final round; this case satisfies the original rule but defeats the converse. A concrete counterexample often exposes the gap more quickly than memorized terminology.
Some generally establishes at least one, not necessarily a majority or all. All A are B does not by itself establish that any A exists unless the passage supplies that existence. An option saying at least one A exists therefore needs additional support. If the passage says some A are not C and all A are B, then at least one B is not C follows through the shared instance. Keep track of which claims concern every member and which identify at least one witness; do not combine two some statements as though they necessarily refer to the same individual.
An outcome changing after an intervention establishes a sequence in time, not automatically a causal effect. A concurrent policy change, a broader trend or a change in who is measured may explain the difference. Ask what else changed and whether the measure itself still means the same thing. Fewer support requests after a help link disappears can reflect reduced access rather than fewer problems. This alternative weakens the inference from requests to problems without proving that the intervention had no beneficial effect at all.
Evidence strengthens when it makes the proposed explanation more plausible relative to alternatives, and weakens when it supplies a relevant challenge. A controlled comparison holding an identified confounder constant can strengthen a causal account. Evidence for the proposed mechanism can also strengthen it. A new fact unrelated to the conclusion's gap does neither merely because it is favorable or unfavorable to the topic. State the bridge explicitly: this fact matters because it rules out this alternative, supports this mechanism or changes this comparison.
If a survey of renewing subscribers is used to characterize all subscribers, the inference relies on the surveyed group being sufficiently informative about the excluded group. A relevant question is whether canceled subscribers judged the layout differently. The argument does not need every subscriber to have identical tastes; that would be stronger than necessary. For a proposed necessary assumption, consider whether denying it would undermine the reasoning. The test targets the inference, not whether the denial makes you personally dislike the conclusion. Distinguish a necessary bridge from a fact that would merely add extra support.
A theater can sell more tickets while earning less ticket revenue if the price reduction outweighs attendance growth. Two facts seem contradictory only if you assume an unstated link, such as more units always meaning more money. Identify the quantities and conditions behind each claim, then look for a scenario in which both hold. An explanation of compatibility does not necessarily establish which scenario actually occurred. For a bounded question, choose the information that addresses the specific tension rather than a general statement about the subject.
Suppose a company uses fewer support requests as evidence that customers encounter fewer problems. Imagine one world in which the product improved and another in which the help link became harder to find while problems stayed constant. If both worlds fit the reported request count, that count alone cannot distinguish the explanations. This thought experiment identifies exactly what additional measurement is needed: direct evidence about problem frequency or support accessibility.
Apply the same method to a survey generalization. Imagine the excluded group agreeing with the sample, then imagine it disagreeing. If the original evidence permits both, the broad conclusion remains uncertain. The exercise does not assert that the unfavorable world is actual; it tests whether the conclusion is compelled by the premises. Keep that distinction explicit when translating a criticism into a selected answer.
After a multiple-answer attempt, record a separate reason for every option, including true options you omitted. A partial correct set may reveal sound reasoning on some claims but still fails the item's exact-set requirement. Preserve that distinction between diagnostic feedback and credit, and use a different passage for the next assessment of transfer.
Do not reverse a conditional or infer a majority from some. A causal alternative need not be proved true to expose that the original evidence fails to isolate a cause. Strengthening is not the same as proving. An assumption should address the argument's actual gap. In a three-option question, all three answers can legitimately be correct.
Read the rule precisely.
Every approved application contains a reference.
Approval implies a reference; the reverse is not stated.
Identify a guaranteed consequence.
An application without a reference is not approved.
This is the contrapositive of the supplied rule.
Test the tempting converse.
An application with a reference might still be rejected.
That possibility is consistent with the original rule.
Choose only the supported direction.
A reference is necessary, not established as sufficient.
No extra criterion for approval has been supplied.
Separate evidence from conclusion.
Surveyed museum members praise an exhibit; the director concludes all local residents favor it.
The evidence comes from one selected subgroup.
Locate the population change.
Museum members are not identical to all residents.
The conclusion includes people outside the sample.
Name a relevant possible difference.
Nonmembers may have different interests or opinions.
That difference would limit the generalization.
Identify useful evaluating evidence.
A comparable survey of nonmembers would bear on the gap.
The missing group directly matches the conclusion's expanded scope.
Avoid an excessive conclusion.
The original survey is not thereby proved false.
It may accurately describe members while failing to establish population-wide approval.
Read the proposed cause.
A new filter is said to reduce contamination because filtered samples had lower counts.
Filtered and unfiltered samples came from different sources.
Identify the alternative explanation.
Source quality could produce the count difference.
The comparison does not yet isolate filtration.
Consider a controlled comparison.
Split samples from one source and filter only one portion of each.
This holds source differences constant within pairs.
Interpret a repeated advantage.
If filtered portions again have lower counts, support for filtration increases.
The identified source explanation becomes less plausible.
Consider mechanism evidence.
Finding contaminants trapped in the filter would add relevant support.
It connects the intervention with a process that could produce the outcome.
Preserve the strength of the conclusion.
The evidence strengthens the account; it need not settle every possible concern.
A strengthen task does not require an absolute guarantee.
Identify the observed change.
Complaints fell after a service removed its complaint form.
The manager concludes that service quality improved.
Name the missing link.
Complaint counts also depend on access to reporting.
Consider a scenario preserving problems while reducing complaints.
State the bounded criticism.
Every sample that passed the laboratory's final screen had first passed its preliminary screen. Some samples passed the preliminary screen but failed the final screen. Select all statements that follow.
Bicycle counts rose after a town opened a cycle path. During the same period, fuel prices rose and employers subsidized bicycle purchases. No comparison town or separate estimate of these influences is available. Select all supported claims.
A publisher surveyed only subscribers who renewed. Most respondents praised a new layout. The publisher generalized that praise to all former subscribers, including those who canceled. Select all limitations of this inference.
All newly cataloged letters were written before 1920. Some pre-1920 letters were not newly cataloged. The curator gives no complete inventory of the collection. Select all statements that follow.
A researcher proposes that a coating prevents corrosion by blocking moisture. Coated samples corroded less than uncoated samples, but their alloys also differed. Alloy composition can affect corrosion. Which findings would strengthen the coating explanation? Select all that apply.
A theater lowered ticket prices and sold more tickets, but total ticket revenue fell. Management had predicted that attendance growth would more than offset the price reduction. Select all supported statements.
Two villages use the same irrigation method but obtain different yields. Their soils, rainfall and seed varieties differ. An observer attributes the difference solely to the shared irrigation method. Select all reasons the attribution is unsupported.
A critic views a play's unresolved ending as deliberate: it forces audiences to reconsider their earlier confidence. She does not claim that every unresolved ending succeeds or that the author intended every effect viewers report. Select all statements compatible with her position.
An island's bird population declined after a predator arrived. A drought also reduced food. Researchers propose comparing nesting success inside predator-free enclosures with success outside while monitoring food availability. Select all descriptions of the study's purpose.
Household fires declined after a town distributed safety leaflets. An analyst asks whether similar towns without leaflets had the same decline during that period. Select all reasons this comparison matters.
Support requests fell after a company removed its homepage help link. An executive inferred that users encountered fewer problems. The report measured neither problem frequency nor ability to find support. Select all statements exposing the inference's uncertainty.
Lesson test: one question per skill, one attempt each, no hints. Your answers are checked when you submit.
Every interviewed applicant submitted a portfolio. Some portfolio submitters were not interviewed. Nothing is stated about portfolio quality. Select all statements that follow.
Tomorrow, turn an all-A-are-B statement into its contrapositive and supply a counterexample to its converse. Then identify a causal alternative in a fresh passage and explain what comparison would help separate the explanations.
17. Complete an alternative-explanation test, step 3
The decline alone does not establish fewer problems.
This challenges the inference without proving that quality could not have improved.