Summary
Probability is the measure of how likely an event is to occur. It is often expressed as a fraction, decimal, or percentage.
- Probability — the likelihood of an event occurring, expressed as a number between 0 and 1. Example: The probability of rolling a 3 on a fair six-sided die is 1/6.
- Mean — the average of a set of numbers, calculated by dividing the sum of the numbers by the count of numbers. Example: The mean of 2, 3, and 4 is (2+3+4)/3 = 3.
- Mode — the number that appears most frequently in a data set. Example: In the data set 2, 3, 3, 4, the mode is 3.
- Sector Angle — the angle that represents a part of a whole in a pie chart, calculated based on the frequency of the data. Example: If a number appears 3 times out of 20, its sector angle in a pie chart is (3/20) * 360° = 54°.
Exam Tips
Key Definitions to Remember
- Probability is the likelihood of an event occurring, expressed as a number between 0 and 1.
- Mean is the average of a set of numbers.
- Mode is the number that appears most frequently in a data set.
Common Confusions
- Confusing probability with certainty — a probability of 1 means certainty, while 0 means impossibility.
- Mixing up mean and median — mean is the average, while median is the middle value.
Typical Exam Questions
- What is the probability of drawing a blue counter from a bag of 16 counters, 4 of which are blue? The probability is 4/16 or 1/4.
- How do you calculate the mean of the numbers 2, 3, and 4? Add the numbers and divide by 3: (2+3+4)/3 = 3.
- What is the mode of the numbers 2, 3, 3, 4? The mode is 3.
What Examiners Usually Test
- Understanding and calculating probabilities in different contexts.
- Ability to calculate mean, mode, and sector angles for data representation.
- Application of probability concepts to real-world scenarios.