ReasoningAbility.com

Inference - Intermediate Level: logical inferences INTERMEDIATE

Master inference concepts through this excellence pursuit practice set. Worksheet 16 of 30 contains 20 intermediate-level problems. Deep dive into logical inferences while learning implied meaning, deductive inference, inductive reasoning. Recommended for mid-level learners aiming for moderate complexity with mixed patterns.

📝 Worksheet 16 of 30 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Intermediate level

What you'll learn in this worksheet:
Your progress through Inference
Worksheet 16 of 30 (53% complete)

Question 1

Observation: Crime rates fell after community policing was implemented What causal inference is most reasonable?
This inference uses temporal precedence (the cause occurred before the effect) and correlation to suggest causation: Community policing likely reduced crime

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

Question 2

Analogical reasoning: "Birds build nests for their young. Bees build hives." What is the most reasonable inference by analogy?
This uses analogical reasoning: Birds build nests for their young. Bees build hives.

The analogy maps relationships from the source domain to the target domain, suggesting: Bees build hives for their young (the hive serves the same protective function as a nest)

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

Question 3

Quantifier logic: • All dogs are mammals • No cats are dogs • Some pets are cats What can be inferred about the relationships?
This tests understanding of quantifiers (all, some, no, most). Some pets are not dogs

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 4

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 5

Observation: The ancient ruins have precise stone cuts. They could have used copper tools, advanced lost technology, or simple wedges and hammers. Which is the most reasonable inference about the cause?
This is abductive reasoning (inference to the best explanation). Given the observation 'The ancient ruins have precise stone cuts. They could have used copper tools, advanced lost technology, or simple wedges and hammers.', we consider possible causes and select the most plausible one. They probably used simple wedges and hammers (most plausible given known technology) is the best explanation because it's the most common, simplest, or most likely cause.
abduction, best-explanation, diagnosis

Question 6

Statistical finding: A drug trial with 500 patients found 80% improved. The control group had 30% improvement. What can you infer about the population?
This uses statistical inference: from a representative sample, we can make probabilistic claims about the population. The drug likely causes improvement (40% improvement over baseline is significant) is the appropriate inference, accounting for sampling error and confidence levels.
sampling, generalization, confidence

Question 7

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 8

Given: No reptiles are warm-blooded. A snake is a reptile. What can you logically conclude?
This is a direct inference. The conclusion follows necessarily from the premise: "No reptiles are warm-blooded. A snake is a reptile." leads to "A snake is not warm-blooded" because the premise establishes a universal relationship and then confirms the condition.
direct, deductive, modus-ponens

Question 9

Statistical information: 7 out of 10 doctors recommend this medication. Your doctor prescribed it. What is the most reasonable inference?
This is probabilistic reasoning. The statistical evidence (7 out of 10 doctors recommend this medication. Your doctor prescribed it.) doesn't guarantee certainty, but it provides strong support for: This medication is probably effective

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

Question 10

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 11

Given these logical premises: • All successful people work hard • Some hard workers are lucky • No lazy people are successful • John is successful Which statement must be true?
This requires multi-step logical deduction:
• All successful people work hard
• Some hard workers are lucky
• No lazy people are successful
• John is successful

Applying logical rules (modus ponens, modus tollens, contrapositive, transitive property, quantifier logic), we can conclude: John works hard
multi-step, quantifier, modal

Question 12

Logical condition: Being over 18 is necessary for voting. John can vote. 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)

John is over 18
necessary-conditions, sufficient-conditions, logic

Question 13

Observation: The cookies are missing from the jar. Either a child took them, or an adult took them, or an animal got them. Which is the most reasonable inference about the cause?
This is abductive reasoning (inference to the best explanation). Given the observation 'The cookies are missing from the jar. Either a child took them, or an adult took them, or an animal got them.', we consider possible causes and select the most plausible one. A child likely took the cookies (most probable given typical household scenarios) is the best explanation because it's the most common, simplest, or most likely cause.
abduction, best-explanation, diagnosis

Question 14

Logical condition: Rain is sufficient for wet ground. The ground is wet. 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)

Cannot conclude it rained (could be sprinklers)
necessary-conditions, sufficient-conditions, logic

Question 15

Observation: Sales increased 40% after the advertising campaign What causal inference is most reasonable?
This inference uses temporal precedence (the cause occurred before the effect) and correlation to suggest causation: The advertising campaign likely caused increased sales

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

Question 16

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 17

Quantifier logic: • All dogs are mammals • No cats are dogs • Some pets are cats What can be inferred about the relationships?
This tests understanding of quantifiers (all, some, no, most). Some pets are not dogs

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 18

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 19

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 20

Consider this argument: "The ancient civilization built huge monuments, so they must have had advanced technology." What unstated assumption must be true for this reasoning to be valid?
The argument makes a hidden assumption: Advanced technology was necessary to build the monuments (and no other explanation like massive labor forces exists)

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
Previous Worksheet Next Worksheet