1. A measure of the chance that an event (or set of events) will occur expressed on a linear scale from 0 (impossibility) to 1 (certainty).

Usage Notes:

  1. Sometimes, probability is expressed as a percentage between 0 and 100%.
  2. Quantitatively, probability is typically expressed as:
    • Mathematical Probability proportion of favourable outcomes to the total number of possibilities if these are indifferent
    • Empirical Probability or the proportion observed in a sample
    • Relative Frequency or the limit of this as the sample size tends to infinity
    • Subjective Probability or by more subjective criteria