Difference Between Probability and Likelihood

Probability vs Likelihood

As the famous proverb goes, “nothing is impossible.” This then proves that individuals shouldn’t shoo away the ideas of possibilities. One cannot be truly sure that an event will occur as change is the only constant thing in this world.

Even scientists and mathematicians alike would agree to this. In fact, there are various studies dedicated to observing both probability and likelihoods. Biologists study the likelihood of an organism to survive a new environment and weather conditions. Chemists and physicists observe the probability of an atom to jump from one quantum to another. Geneticists monitor the probability of peas getting the characteristics of the parent plant.

Likelihood and probability are everywhere. Then again, very few know the differences between the two.
In a non-technical parlance, the two terms are synonymous. Both “likelihood” and “probability” expresses odds of occurrences. Philosophically speaking, the two words have the same denotative meaning. Then again, these two words are strictly used in different contexts.

“Probability” refers to the percentage of chances of foreseen outcomes based on parameters of values. On the other hand, “likelihood” refers to the possibility of occurrences with different sets of parameter values that may lead to a sound conclusion.

Simply put, probability points to chances while likelihood denotes a possibility. For example, one can correctly say, “There is high likelihood of rain today.” On the other hand, a meteorologist might express the chances by saying, “The probability of getting six on a single, rolling dice is one out of six.”

This being said, it is reasonable to infer that a probability involves the computation of chances done with formulas carefully established by mathematicians. On the other hand, a likelihood serves as an inference or forecasts that do not involve the use of a solid basis or theory.

While this may be confusing, experts have come up with a system that can give clues on the proper usage of both terms. It had always been interesting to note that both the terms “likelihood” and “probability” are always followed by the preposition “of.” Remember, though, that “likelihood” takes an adverbial form of the word “likely” and the adjectival form of “like.”

The term “likelihood,” therefore, indicates the state of “being like” as in the expression “in all likelihood.” Meaning, there is still a possibility of an event to not occur no matter how likely it is to happen.

On the other hand, “probability” indicates the meaning of “being probable” or simply “chancy” similar to the expression “in all probability.” Therefore, it should be used to refer to something with a precise state or condition of being probable. It would still be the same with “likelihood,” but “probability” shows an exact chance of occurrence.

Its being derived from “permutation” and “combination” during a careful statistical application, “probability” gives individuals a forecast of occurrence based on applied theories and formulations.

Take, for example, a scenario with two individuals conversing. One says there is a high likelihood for the storm to hit their country because of the close proximity of the storm’s tail to their area of responsibility. He cannot assert the probability because he has not looked into the statistics and numbers that can speak of the possible chances of the storm changing direction.

The other person, being able to watch the news and get pertinent data, will then agree and say, “There are seven out of ten chances that the storm will hit our country.” This is a more precise prediction as there had been clear parameters for his conclusion.

Summary:

1.“Probability” and “likelihood” can be both used to express a prediction and odds of occurrences.
2.“Probability” refers to a “chance” while likelihood refers to a “possibility.”
3.A probability follows clear parameters and computations while a likelihood is based merely on observed factors.

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