Because the objective interpretation of probability is based on the notion of limiting frequency, its applicability is limited to experimental situations that are repeatable. Yet the language of probability is often used in connection with situations that are inherently unrepeatable.
Example
- “The chances are good for a peace agreement”
- “It is likely that our company will be awarded the contract”
- “Because their best quarterback is injured, I expect them to score no more than 10 points against us.”
In such situations we would like, as before, to assign numerical probabilities to various outcomes and events (e.g., the probability is .9 that we will get the contract). This necessitates adopting an alternative interpretation of these probabilities. Because different observers may have different prior information and opinions concerning such experimental situations, probability assignments may now differ from individual to individual. Interpretations in such situations are thus referred to as subjective. The book by Robert Winkler listed in the chapter references gives a very readable survey of several subjective interpretations.