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Four types of probabilities
Authors: David B. SouthPublication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2009, Issue N.Z.J.For. 54(4) 2010, pp 46-47, Jan 2010
Publisher: New Zealand Institute of Forestry
Abstract: The term “probability” has several definitions. I prefer the following: a quantitative description of the likely occurrence of a particular event. Probability is often expressed on a scale from 0 to 100% but researchers often use a scale of 0 to 1; a rare event has a probability close to 0 while a very common event has a probability close to 1. Probabilities are used as a tool to support conclusions regarding both controlled and “natural” experiments. I deal mostly with probabilities derived from controlled and natural experiments but only recently did I realize there are other types of probabilities. My reason for writing this essay is to point out that not all probabilities are created equal; some are simply guesses. Unfortunately, information about the origin of the probabilities has not been communicated clearly or consistently (NOAA 2009).