Final Probability Checkpoint
Section A: Foundations
- Define experiment, outcome and event.
- Place 0.8 on the probability scale and describe its likelihood.
- A fair spinner has 8 equal sectors, 3 yellow. Find P(yellow).
- In 200 trials an event happens 74 times. Find experimental probability.
Section B: Combined Events
- Two fair coins are tossed. Find P(exactly one head).
- Two dice are rolled. Find P(sum greater than 10).
- P(A)=0.6, P(B)=0.45 and P(Aβ©B)=0.2. Find P(AβͺB).
- Independent events have P(A)=0.3 and P(B)=0.7. Find P(Aβ©B).
Section C: Trees and Applications
- A bag contains 6 red and 4 blue counters. Two are selected with replacement. Find P(two red).
- Repeat without replacement.
- Find P(at least one blue without replacement).
- An event has probability 0.14. Find expected frequency in 600 trials.
- Explain why expected and observed frequencies need not match exactly.
β Check Your Work
Show answers and working
- Experiment: uncertain process; outcome: one possible result; event: one or more outcomes of interest.
- 0.8 lies near certainty and may be described as very likely.
- 3/8.
- 74/200=37/100=0.37.
- HT or TH: 1/4+1/4=1/2.
- Sums 11 or 12: 3/36=1/12.
- 0.6+0.45β0.2=0.85.
- 0.3Γ0.7=0.21.
- 6/10Γ6/10=36/100=9/25.
- 6/10Γ5/9=30/90=1/3.
- 1βP(two red)=1β1/3=2/3.
- 0.14Γ600=84.
- Expected frequency is a long-run model; random variation changes observed results in a particular experiment.
π― Final Interactive Checkpoint
Answer five randomly selected probability questions.
Score: 0/0
Revision Guidance and Readiness
- Attempt the questions without notes first.
- Use the answers or worked solutions to identify the exact step that needs attention.
- Return to the relevant lesson, then retry missed questions.
- You are ready to move on when you can explain your method and check your result independently.