Year 9 Maths — Probability from experiments
Work out the empirical probability of an event from the results a trial actually gave.
Name: ________________________
Before you start
Every probability there has ever been lives somewhere on this line. Move along it and read off the values.
Zero means it never happened and one means it happened every single time. Nothing sits outside the two ends — a probability of 1.4 or of -0.2 is not unlikely, it is impossible.
1.A die is rolled 60 times and shows a six on 12 of them. What is the empirical probability of a six? Give your answer as a fraction.
2.A coin is tossed 100 times and lands heads 54 times. What is the empirical probability of a head? Give your answer as a fraction.
3.An event has an empirical probability of 0.7. Tap where that sits on the probability line.
Mark the line with an X.
4.A batch of 50 bulbs was tested and 3 of them were faulty. What is the empirical probability that a bulb is faulty? Give your answer as a decimal.
5.In a trial, seeds germinated with an empirical probability of 0.8. Out of 500 more seeds, how many would you expect to germinate?
6.Sort each number by whether it could possibly be a probability.
Groups: Could be a probability · Could not be a probability
- 0.25
- 7/5
- -0.2
- 1.4
- 1
- 0
7.A coin gives 7 heads in 10 tosses, and 503 heads in 1000 tosses. Which empirical probability is closer to the theoretical one half?
- a) They are exactly as close as each other
- b) Neither is anywhere near
- c) The one from 10 tosses
- d) The one from 1000 tosses
8.A coin is tossed 100 times and lands heads 54 times. What is the empirical probability of a tail? Give your answer as a fraction.
Answer key — Year 9 Maths — Probability from experiments
- 1. 12/60
- 2. 54/100
- 3. 0.7
- 4. 0.06
- 5. 400
- 6. 0.25 → Could be a probability; 1.4 → Could not be a probability; 0 → Could be a probability; -0.2 → Could not be a probability; 1 → Could be a probability; 7/5 → Could not be a probability
- 7. d) The one from 1000 tosses
- 8. 46/100