To determine which of the given statements describe a probability, we need to understand the fundamental properties of probability.
1. It is always expressed as a percentage.
- This statement is not correct. Probabilities can be expressed in various forms including fractions (e.g., 1/2), decimals (e.g., 0.5), and percentages (e.g., 50%). Therefore, it's not always expressed as a percentage.
2. It is a number between 0 and 1 inclusive.
- This statement is true. Probabilities are always within the range of 0 to 1, inclusive. A probability of 0 means an event is impossible, while a probability of 1 means an event is certain.
3. A probability lies between minus one and plus one.
- This statement is incorrect. Probabilities cannot be negative. They must be within the range of 0 to 1, which does not include negative values or values greater than 1.
4. It describes the relative likelihood that an event will occur.
- This statement is true. Probability is a measure of the likelihood or chance that a particular event will happen.
Based on this analysis, the statements that accurately describe a probability are:
- It is a number between 0 and 1 inclusive.
- It describes the relative likelihood that an event will occur.
Thus, the correct selections are:
2 and 4
