Math 9 · Unit 12: Probability · Cambridge Lower Secondary Maths Stage 9

Questions

1. 1. Four coins are flipped together and the number of heads is recorded. This is repeated 50 times. The table shows the results. Work out the relative frequency of 2 heads. Give your answer as a decimal.

   • 0.46
   • 0.5
   • 0.23
   • 23
   Check

2. 2. Four coins are flipped together and the number of heads is recorded. This is repeated 50 times. The table shows the results. Work out the relative frequency of more than 2 heads. Give your answer as a decimal.

   • 0.64
   • 0.02
   • 0.16
   • 0.18
   Check

3. 3. Four coins are flipped together and the number of heads is recorded. This is repeated 50 times. The table shows the results. Work out the relative frequency of less than 2 heads. Give your answer as a decimal.

   • 0.32
   • 0.82
   • 0.36
   • 0.04
   Check

4. 4. A spinner has two colours, red (R) and blue (B). Here are the results of 20 spins: B R R R B R B R R B B B B R B B R R B B. Work out the relative frequency of red.

   • 0.35
   • 0.45
   • 9
   • 0.55
   Check

5. 5. A spinner has two colours, red (R) and blue (B). Here are the results of 20 spins: B R R R B R B R R B B B B R B B R R B B. Here are the results of another 20 spins: B B B B R B B R R R B B B B B B B B B B. Work out the relative frequency of red based on all 40 spins.

   • 0.2
   • 0.65
   • 0.325
   • 0.45
   Check

6. 6. A spinner has two colours, red (R) and blue (B). In 40 spins red came up 13 times (a relative frequency of 0.325). Arun says: "The probability of red is 0.35." Do the relative frequencies support this conjecture?

   • Yes
   • No
   Check

7. 7. A coin is flipped until it shows a head and the number of flips is recorded. This is repeated 50 times. The table shows the results. Work out the relative frequency of one flip to get a head.

   • 0.29
   • 29
   • 0.58
   • 0.5
   Check

8. 8. A coin is flipped until it shows a head and the number of flips is recorded. This is repeated 50 times. The table shows the results. Work out the relative frequency of 3 or more flips to get a head.

   • 0.06
   • 0.42
   • 0.14
   • 7
   Check

9. 9. A spinner is divided into 10 equal sectors. Some of the sectors are coloured green. The table shows the frequency of landing on green after different numbers of spins. What is the relative frequency of landing on green after 25 spins?

   • 0.68
   • 0.17
   • 0.7
   • 1.47
   Check

10. 10. A spinner is divided into 10 equal sectors. Some of the sectors are coloured green. The table shows the frequency of landing on green after different numbers of spins. Find the relative frequency of landing on green after 100, 200 and 500 spins.

    • 0.7, 0.785 and 0.782
    • 0.7, 0.875 and 0.782
    • 70, 157 and 391
    • 0.07, 0.157 and 0.391
    Check

11. 11. A spinner is divided into 10 equal sectors. Some of the sectors are coloured green. The table shows the frequency of landing on green after different numbers of spins. Estimate the number of sectors that are green.

    • 39
    • 7
    • 8
    • 4
    Check

12. 12. Zara looks at the cars passing her school. She counts how many cars are silver and writes down the total after every 10 cars. Complete the relative frequencies in the table.

    Fill the blanks with these.

    • 0.388
    • 0.25
    • 0.38
    • 0.383
    • 0.45
    • 0.37
    • 0.4
    • 0.386
    Check

13. 13. Zara looks at the cars passing her school. She counts how many cars are silver and writes down the total after every 10 cars. The table shows the results. Estimate the probability of a silver car.

    • about 0.31
    • about 0.2
    • about 0.5
    • about 0.39
    Check

14. 14. Marcus flips two coins. After every 20 flips he records the frequency of two heads. Complete the relative frequencies in the table.

    Fill the blanks with these.

    • 0.225
    • 0.0475
    • 0.19
    • 0.17
    • 0.2125
    • 0.45
    Check

15. 15. Arun carries out the same experiment as Marcus, flipping two coins and recording the frequency of two heads after every 20 flips. Complete the relative frequencies in his table.

    Fill the blanks with these.

    • 0.37
    • 0.4
    • 0.275
    • 0.55
    • 0.267
    • 0.25
    Check

16. 16. You flip a coin 10 times and work out the relative frequency of the coin landing on tails. Which calculation gives it?

    • number of tails × 10
    • 10 ÷ number of tails
    • number of tails + 10
    • number of tails ÷ 10
    Check

17. 17. What is the probability of a fair coin landing on a tail?

    • 0.29
    • 1
    • 0.5
    • 0.58
    Check

18. 18. A fair dice is rolled. What is the probability of getting a particular digit, for example 4? Your relative frequencies from the rolls should be close to this for large samples.

    • 1/3
    • 1/5
    • 1/6
    • 1/10
    Check