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Inference - Expert Level: possible inference EXPERT

Comprehensive self assessment worksheet covering 20 expert-level inference problems. Worksheet 28 of 30 emphasizes possible inference. Master implicit information, conclusion drawing, logical deduction through detailed explanations. Difficulty: challenging problems and time-bound practice. Tailored for expert-level preparation.

📝 Worksheet 28 of 30 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Expert level

What you'll learn in this worksheet:
Your progress through Inference
Worksheet 28 of 30 (93% complete)

Question 1

Logical condition: Fuel is necessary for a car to run. The car is running. 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)

It has fuel
necessary-conditions, sufficient-conditions, logic

Question 2

Consider this argument: "John got promoted quickly. He must have worked very hard." What unstated assumption must be true for this reasoning to be valid?
The argument makes a hidden assumption: Hard work leads to quick promotion (and no other factors like luck, connections, or timing influenced the promotion)

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 3

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 4

Statistical finding: Testing 1000 light bulbs found average lifespan of 1200 hours with standard deviation 100 hours. What can you infer about the population?
This uses statistical inference: from a representative sample, we can make probabilistic claims about the population. Most bulbs last between 1100-1300 hours (within one standard deviation) is the appropriate inference, accounting for sampling error and confidence levels.
sampling, generalization, confidence

Question 5

Consider these premises: • All doctors are educated • Some educated people are rich • Dr. Smith is a doctor Which conclusion logically follows?
By combining the premises logically:
• All doctors are educated
• Some educated people are rich
• Dr. Smith is a doctor

We can deduce: Dr. Smith is educated

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

Question 6

Observation: Plant growth increased by 60% after adding fertilizer What causal inference is most reasonable?
This inference uses temporal precedence (the cause occurred before the effect) and correlation to suggest causation: Fertilizer likely caused better plant growth

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

Question 7

Given: Every square is a rectangle. This shape is a square. What can you logically conclude?
This is a direct inference. The conclusion follows necessarily from the premise: "Every square is a rectangle. This shape is a square." leads to "This shape is a rectangle" because the premise establishes a universal relationship and then confirms the condition.
direct, deductive, modus-ponens

Question 8

Rule: If it's a square, it has four sides Observation: This shape doesn't have four sides What can you logically infer?
This uses the contrapositive rule. The statement "If it's a square, it has four sides" is logically equivalent to its contrapositive: 'If NOT consequence, then NOT condition.' Since we observe "This shape doesn't have four sides" (the consequence is false), we can conclude "This is not a square" (the condition is false).
contrapositive, modus-tollens

Question 9

Given these logical premises: • Either John or Mary broke the vase • If John broke it, he would admit it • John didn't admit it Which statement must be true?
This requires multi-step logical deduction:
• Either John or Mary broke the vase
• If John broke it, he would admit it
• John didn't admit it

Applying logical rules (modus ponens, modus tollens, contrapositive, transitive property, quantifier logic), we can conclude: Mary broke the vase
multi-step, quantifier, modal

Question 10

Observation: Several employees quit last month. Reasons could include low salary, poor management, better opportunities, or relocation. Which is the most reasonable inference about the cause?
This is abductive reasoning (inference to the best explanation). Given the observation 'Several employees quit last month. Reasons could include low salary, poor management, better opportunities, or relocation.', we consider possible causes and select the most plausible one. Better opportunities elsewhere is likely (most common reason for voluntary turnover) is the best explanation because it's the most common, simplest, or most likely cause.
abduction, best-explanation, diagnosis

Question 11

Quantifier logic: • Every musician can read music • Some singers cannot read music What can be inferred about the relationships?
This tests understanding of quantifiers (all, some, no, most). Some singers are not musicians

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 12

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 13

Consider these premises: • No reptiles are warm-blooded • All snakes are reptiles • Python is a snake Which conclusion logically follows?
By combining the premises logically:
• No reptiles are warm-blooded
• All snakes are reptiles
• Python is a snake

We can deduce: Python is not warm-blooded

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

Question 14

Given: All students carry books. John is a student. What can you logically conclude?
This is a direct inference. The conclusion follows necessarily from the premise: "All students carry books. John is a student." leads to "John carries books" because the premise establishes a universal relationship and then confirms the condition.
direct, deductive, modus-ponens

Question 15

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 16

Observation: Customer complaints dropped by 70% after improving service training What causal inference is most reasonable?
This inference uses temporal precedence (the cause occurred before the effect) and correlation to suggest causation: Service training likely reduced complaints

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

Question 17

Consider these premises: • All squares are rectangles • No rectangles are circles • This shape is a square Which conclusion logically follows?
By combining the premises logically:
• All squares are rectangles
• No rectangles are circles
• This shape is a square

We can deduce: This shape is not a circle

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

Question 18

Consider these premises: • If you save money, you become wealthy • If you become wealthy, you can travel • Emma saves money Which conclusion logically follows?
By combining the premises logically:
• If you save money, you become wealthy
• If you become wealthy, you can travel
• Emma saves money

We can deduce: Emma can travel

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

Question 19

Quantifier logic: • Every musician can read music • Some singers cannot read music What can be inferred about the relationships?
This tests understanding of quantifiers (all, some, no, most). Some singers are not musicians

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 20

Logical condition: A touchdown is sufficient for scoring points. The team scored a touchdown. 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)

They scored points
necessary-conditions, sufficient-conditions, logic
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