Basic Probability Definition

Probability · Axiom Academy

LESSON Basic Probability Definition Understanding how to calculate and interpret probability values When all outcomes in a sample space are equally likely , the probability of an event A is the ratio of favorable outcomes to total outcomes. Let's visualize this with rolling a die and finding P(even number): The frequency interpretation defines probability as the long-run proportion of times an event occurs in repeated experiments. Watch how the relative frequency stabilizes over many coin flips: Subjective probability represents a personal degree of belief about the likelihood of an event, based on available information and judgment. Different people may assign different subjective probabilities to the same event: Regardless of the interpretation, all probabilities must satisfy certain fundamental properties. Let's visualize the probability scale:

This is the written version of the interactive lesson above. See the full Probability course.