Example 1 · level 1
A school cricket team won 10 of its last 20 matches. What is the empirical probability that it wins a match? (answer as a fraction)
Show solution
- Wins = 10, matches = 20.
- P = 10/20 = 1/2.
Answer: 1/2
CLASS 9 MATHS · PROBABILITY
Experimental (empirical) probability
Empirical probability of an event = number of trials in which it happened ÷ total number of trials.
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Worked examples
Example 2 · level 2
A bulb factory tested 300 bulbs and found 20 defective. What is the probability that a bulb picked at random is not defective? (answer as a fraction)
Show solution
- Not defective = 300 − 20 = 280.
- P = 280/300 = 14/15.
Answer: 14/15
Example 3 · level 3
Two coins were tossed 76 times: 2 heads came up 21 times, 1 head 33 times, and 0 heads 22 times. What is the empirical probability of getting at least one head? (answer as a fraction)
Show solution
- At least one head = 1 head + 2 heads = 33 + 21 = 54.
- P = 54/76 = 27/38.
Answer: 27/38