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Inference - Expert Level: inference strength EXPERT

Intensive progress check 🎯 drill: 20 expert-level inference questions. Worksheet 30 of 30 hones your inference strength abilities. Practice implied meaning, deductive inference, inductive reasoning under timed conditions. Best for expert-level students seeking challenging problems and time-bound practice.

📝 Worksheet 30 of 30 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Expert level

What you'll learn in this worksheet:
Your progress through Inference
Worksheet 30 of 30 (100% complete)

Question 1

Analogical reasoning: "The CEO guides a company like a captain guides a ship." What is the most reasonable inference by analogy?
This uses analogical reasoning: The CEO guides a company like a captain guides a ship.

The analogy maps relationships from the source domain to the target domain, suggesting: The CEO is responsible for the company's direction and safety, just as a captain is for a ship

Analogical inferences are suggestive but not logically certain; the strength depends on the relevance and similarity of the mapped features.
analogy, metaphor, mapping

Question 2

Given: All birds have wings. A sparrow is a bird. What can you logically conclude?
This is a direct inference. The conclusion follows necessarily from the premise: "All birds have wings. A sparrow is a bird." leads to "A sparrow has wings" because the premise establishes a universal relationship and then confirms the condition.
direct, deductive, modus-ponens

Question 3

Statistical information: Only 10% of unprepared students get good grades. Sam is unprepared. What is the most reasonable inference?
This is probabilistic reasoning. The statistical evidence (Only 10% of unprepared students get good grades. Sam is unprepared.) doesn't guarantee certainty, but it provides strong support for: Sam will likely not get good grades

Remember: Probability inferences are about likelihood, not certainty.
probabilistic, statistical, likelihood

Question 4

Observation: Traffic accidents decreased by 50% after installing speed cameras What causal inference is most reasonable?
This inference uses temporal precedence (the cause occurred before the effect) and correlation to suggest causation: Speed cameras likely reduced traffic accidents

However, be aware of alternative explanations (confounding variables, regression to the mean, etc.) that might also explain the observation.
causation, temporal, correlation

Question 5

Logical condition: Practice is necessary for mastery. Sarah has mastery. What can you infer?
This tests necessary vs. sufficient conditions.

- If A is SUFFICIENT for B: A → B (A guarantees B, but B can happen without A)
- If A is NECESSARY for B: B → A (B cannot happen without A)

Sarah practiced
necessary-conditions, sufficient-conditions, logic

Question 6

Consider these premises: • All programmers write code • Some code contains bugs • Alice is a programmer Which conclusion logically follows?
By combining the premises logically:
• All programmers write code
• Some code contains bugs
• Alice is a programmer

We can deduce: Alice writes code

This uses 3-step logical reasoning, applying transitive properties and categorical logic.
syllogism, chain-reasoning

Question 7

Statistical finding: Of 50 randomly selected days, 40 were sunny. The region has 365 days per year. What can you infer about the population?
This uses statistical inference: from a representative sample, we can make probabilistic claims about the population. Approximately 292 days per year are sunny in this region (80% of days) is the appropriate inference, accounting for sampling error and confidence levels.
sampling, generalization, confidence

Question 8

Given these logical premises: • All A are B • No B are C • All D are A • Some E are D Which statement must be true?
This requires multi-step logical deduction:
• All A are B
• No B are C
• All D are A
• Some E are D

Applying logical rules (modus ponens, modus tollens, contrapositive, transitive property, quantifier logic), we can conclude: Some E are not C
multi-step, quantifier, modal

Question 9

Observation: The car won't start. Possible causes: dead battery, empty gas tank, starter problem, or electrical issue. Which is the most reasonable inference about the cause?
This is abductive reasoning (inference to the best explanation). Given the observation 'The car won't start. Possible causes: dead battery, empty gas tank, starter problem, or electrical issue.', we consider possible causes and select the most plausible one. The battery is probably dead (most common cause) is the best explanation because it's the most common, simplest, or most likely cause.
abduction, best-explanation, diagnosis

Question 10

Rule: If you're over 18, you can vote Observation: Sarah cannot vote What can you logically infer?
This uses the contrapositive rule. The statement "If you're over 18, you can vote" is logically equivalent to its contrapositive: 'If NOT consequence, then NOT condition.' Since we observe "Sarah cannot vote" (the consequence is false), we can conclude "Sarah is under 18" (the condition is false).
contrapositive, modus-tollens

Question 11

Consider this argument: "The new restaurant is always crowded. The food must be excellent." What unstated assumption must be true for this reasoning to be valid?
The argument makes a hidden assumption: Crowded restaurants indicate excellent food (and not factors like location, price, or marketing)

This assumption is not explicitly stated but is necessary for the conclusion to follow from the premises. If this assumption is false, the argument becomes weak or invalid.
assumption, critical-thinking, argument-analysis

Question 12

Quantifier logic: • Most students passed math • Most students passed science What can be inferred about the relationships?
This tests understanding of quantifiers (all, some, no, most). Some students passed both subjects

Remember: 'Some' means 'at least one' (could be all). 'Most' means 'more than half'. No categorical statement about individuals follows from 'most' statements.
quantifiers, all-some-none, logic

Question 13

Statistical finding: Of 50 randomly selected days, 40 were sunny. The region has 365 days per year. What can you infer about the population?
This uses statistical inference: from a representative sample, we can make probabilistic claims about the population. Approximately 292 days per year are sunny in this region (80% of days) is the appropriate inference, accounting for sampling error and confidence levels.
sampling, generalization, confidence

Question 14

Consider this argument: "Most successful entrepreneurs dropped out of college. If you want to be successful, you should drop out." What unstated assumption must be true for this reasoning to be valid?
The argument makes a hidden assumption: College education prevents success (and the correlation represents causation)

This assumption is not explicitly stated but is necessary for the conclusion to follow from the premises. If this assumption is false, the argument becomes weak or invalid.
assumption, critical-thinking, argument-analysis

Question 15

Analogical reasoning: "A heart pumps blood through the body. A water pump circulates water through a system." What is the most reasonable inference by analogy?
This uses analogical reasoning: A heart pumps blood through the body. A water pump circulates water through a system.

The analogy maps relationships from the source domain to the target domain, suggesting: The heart is the body's central circulatory pump

Analogical inferences are suggestive but not logically certain; the strength depends on the relevance and similarity of the mapped features.
analogy, metaphor, mapping

Question 16

Given: All mammals breathe air. A dolphin is a mammal. What can you logically conclude?
This is a direct inference. The conclusion follows necessarily from the premise: "All mammals breathe air. A dolphin is a mammal." leads to "A dolphin breathes air" because the premise establishes a universal relationship and then confirms the condition.
direct, deductive, modus-ponens

Question 17

Consider these premises: • If you're tired, you sleep • If you sleep, you dream • John is tired Which conclusion logically follows?
By combining the premises logically:
• If you're tired, you sleep
• If you sleep, you dream
• John is tired

We can deduce: John will dream

This uses 3-step logical reasoning, applying transitive properties and categorical logic.
syllogism, chain-reasoning

Question 18

Given these logical premises: • If it's a weekday, I work • If I work, I get tired • If I'm tired, I sleep early • I didn't sleep early Which statement must be true?
This requires multi-step logical deduction:
• If it's a weekday, I work
• If I work, I get tired
• If I'm tired, I sleep early
• I didn't sleep early

Applying logical rules (modus ponens, modus tollens, contrapositive, transitive property, quantifier logic), we can conclude: It's not a weekday
multi-step, quantifier, modal

Question 19

Logical condition: Practice is necessary for mastery. Sarah has mastery. What can you infer?
This tests necessary vs. sufficient conditions.

- If A is SUFFICIENT for B: A → B (A guarantees B, but B can happen without A)
- If A is NECESSARY for B: B → A (B cannot happen without A)

Sarah practiced
necessary-conditions, sufficient-conditions, logic

Question 20

Given these logical premises: • If A, then B • If B, then C • If C, then not D • A is true Which statement must be true?
This requires multi-step logical deduction:
• If A, then B
• If B, then C
• If C, then not D
• A is true

Applying logical rules (modus ponens, modus tollens, contrapositive, transitive property, quantifier logic), we can conclude: D is false
multi-step, quantifier, modal
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