Class 9 Computer & AI Chapter 4: Probability & Confidence — practice questions with answers
Free practice for Class 9 Computer & AI, Chapter 4: Probability & Confidence. Try the solved questions below, then take a free test with instant marking and explanations.
45 questions19 easy, 16 medium, 10 hardNCERT · CBSE · State boards
Sample questions with solutions
Q1. A spam filter says ‘I am 87% sure this is spam’. What is the 87%?
- A probability — the model’s confidence
- The number of spam emails
- The model’s speed
- The size of the email
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Answer: A. A probability — the model’s confidence
Why: AI gives confidence, not just answers. [AI for New Learner — Senior 1, Ch 4]
Why: AI gives confidence, not just answers. [AI for New Learner — Senior 1, Ch 4]
Q2. Which statement about any probability P is always true?
- 0 ≤ P ≤ 1
- P can be any number
- P is always more than 1
- P is always 0.5
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Answer: A. 0 ≤ P ≤ 1
Why: P = 0 impossible, P = 1 certain. [AI for New Learner — Senior 1, Ch 4]
Why: P = 0 impossible, P = 1 certain. [AI for New Learner — Senior 1, Ch 4]
Q3. For one event, what do the probabilities of all possible outcomes add up to?
- Exactly 1
- Exactly 0
- 100 times the number of outcomes
- It depends on luck
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Answer: A. Exactly 1
Why: Σ P(all outcomes) = 1. [AI for New Learner — Senior 1, Ch 4]
Why: Σ P(all outcomes) = 1. [AI for New Learner — Senior 1, Ch 4]
Q4. A fair 6-sided die is rolled. What is P(rolling a 4)? (to 3 decimal places)
Show answer
Answer: 0.167 (± 0.001)
Why: 1 favourable outcome out of 6. [AI for New Learner — Senior 1, Ch 4]
Why: 1 favourable outcome out of 6. [AI for New Learner — Senior 1, Ch 4]
Q5. A fair 6-sided die is rolled. What is P(rolling an odd number)?
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Answer: 0.5 (± 0)
Why: 3 of 6 outcomes are odd. [AI for New Learner — Senior 1, Ch 4]
Why: 3 of 6 outcomes are odd. [AI for New Learner — Senior 1, Ch 4]
Q6. P(rain tomorrow) = 0.3. What is P(no rain tomorrow)?
Show answer
Answer: 0.7 (± 0)
Why: 1 − 0.3 = 0.7. [AI for New Learner — Senior 1, Ch 4]
Why: 1 − 0.3 = 0.7. [AI for New Learner — Senior 1, Ch 4]
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How many practice questions are there for Class 9 Computer & AI Chapter 4: Probability & Confidence?
45 questions (19 easy, 16 medium, 10 hard). A few are solved on this page; the free test shows the answer and explanation for every question after you submit.
Is this chapter from the NCERT book?
Yes — it follows the NCERT Class 9 Computer & AI syllabus, used by CBSE and many state boards.