Probability Single Event
The probability of a single event measures how likely an event is to occur. It is calculated by dividing the number of favourable outcomes by the total number of possible outcomes. The probability value ranges from 0 to 1, where 0 means the event is impossible and 1 means it is certain.
Related Lessons:
What is Probability?
In general, to find the probability of a single event:
\(P\left(E\right)=\frac{\text{number of ways event E can happen}}{\text{total number of ways ALL possible events can happen}}\)
and \(0≤P(E)≤1\).
What Is Possibility Diagram?
A possibility diagram is a visual method used to list all possible outcomes of an event in an organized way. It uses tables to show every combination that can occur, especially when dealing with two or more stages (such as tossing coins or choosing items). This helps students clearly visualise all outcomes, making it easier to calculate probabilities and identify favourable outcomes.
Example 1
- the ball is red,
- the ball is not white,
- the ball is green or blue
Example 2
A bag contains 25 balls of which \(x\) balls are black.
After 5 black balls are removed from the bag, the probability of getting a black ball is decreased by \(\frac{1}{10}\).
Calculate the value of \(x\).
Example 3
A bag contained 6 blue balls and 7 red balls. If a ball is picked at random from the bag, find the probability that
- a red ball is picked
- a green ball is picked