Calculating theoretical probabilities from Venn diagrams (one event) | Maths

Starter quiz

What is the probability that this spinner will land on either L or T?
- 0.4 ✓
- 0.2
- 0.6
A coin is flipped twice. How many possible outcomes will be in the sample space?
- 2
- 4 ✓
- 3
If the probability of an event (A) is 1/6, and the experiment is repeated 78 times, what is the theoretical number of times (A) will occur?
- 13 ✓
- 6
- 36
- 18
In a bag with 5 red counters and 3 green counters, what is the probability of randomly selecting a red counter?
- $/frac{5}{3}$
- $/frac{5}{8}$ ✓
- $/frac{2}{5}$
In a bag with 5 red counters, 2 blue counters and 3 green counters, what is the probability of randomly selecting a blue counter?
- $/frac{1}{5}$ ✓
- $/frac{2}{9}$
- $/frac{7}{10}$
In a fair six-sided die, what is the probability (as a decimal) of rolling an even number and getting a head in a single toss of a fair coin?
- '0.25' ✓

Which of the following is the correct data set for A?
- {2, 4, 7} ✓
- {2, 4}
- {7}
- {2,4,5,7}
When throwing a fair sided die, what is the probability of not getting a 6?
- $\frac{1}{6}$
- $\frac{6}{6}$
- $\frac{5}{6}$ ✓
What is the intersection of the sets A {𝜷, 𝜸, 𝜹} and B {𝜷, 𝜽}
- {𝜷} ✓
- {𝜷, 𝜸, 𝜹, 𝜽}
- {𝜷, 𝜷, 𝜸, 𝜹, 𝜽}
Which of the following is the correct data set for B?
- {4,2}
- {4,2,7}
- {7}
- {5}
- {5,7} ✓
When throwing a fair sided die, what is the probability of not getting a multiple of 3?
- $\frac{1}{3}$ ✓
- $\frac{1}{6}$
- $\frac{1}{4}$
- $\frac{5}{6}$
What is the correct set of outcomes, ξ , shown in this Venn diagram?
- ξ = {2,4,5,7} ✓
- ξ = {2,4,7}
- ξ = {7}

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The probability of an outcome can be found by considering a Venn diagram showing all possible outcomes.
The probability of a set of outcomes can be found by considering a Venn diagram showing all possible outcomes.
A Venn diagram can help us find a probability, even when the outcomes are not equally likely.

Pupils may count the number of outcomes and state this as the probability.

Remind pupils that the probability scale is between 0 and 1, so an answer of 3 is not correct.

Venn diagram - Venn diagrams are a representation used to model statistical/probability questions. Commonly circles are used to represent events.
Theoretical probability - A theoretical probability is a probability based on counting the number of desired outcomes from a sample space where all individual outcomes are equally likely.