probability

[ prob-uh-bil-i-tee ]

noun

, plural prob·a·bil·i·ties.

1. the quality or fact of being probable.
2. a strong likelihood or chance of something:

   The probability of the book's success makes us optimistic.

3. a probable event, circumstance, etc.:

   Our going to China is a probability.

4. Statistics.
   1. the relative possibility that an event will occur, as expressed by the ratio of the number of actual occurrences to the total number of possible occurrences.
   2. the relative frequency with which an event occurs or is likely to occur.

probability

/ ˌprɒbəˈbɪlɪtɪ /

noun

1. the condition of being probable
2. an event or other thing that is probable
3. statistics a measure or estimate of the degree of confidence one may have in the occurrence of an event, measured on a scale from zero (impossibility) to one (certainty). It may be defined as the proportion of favourable outcomes to the total number of possibilities if these are indifferent ( mathematical probability ), or the proportion observed in a sample ( empirical probability ), or the limit of this as the sample size tends to infinity ( relative frequency ), or by more subjective criteria ( subjective probability )

probability

/ prŏb′ə-bĭl′ĭ-tē /

1. A number expressing the likelihood of the occurrence of a given event, especially a fraction expressing how many times the event will happen in a given number of tests or experiments. For example, when rolling a six-sided die, the probability of rolling a particular side is 1 in 6, or 1 6 .

probability

1. A number between zero and one that shows how likely a certain event is. Usually, probability is expressed as a ratio : the number of experimental results that would produce the event divided by the number of experimental results considered possible. Thus, the probability of drawing the ten of clubs from an ordinary deck of cards is one in fifty-two (1:52), or one fifty-second.

Other Words From

• nonprob·a·bili·ty noun plural nonprobabilities
• super·proba·bili·ty noun plural superprobabilities

Word History and Origins

Origin of probability¹

From the Latin word probābilitās, dating back to 1545–55. See probable, -ity

Idioms and Phrases

Idioms

1. in all probability, very probably; quite likely:

   The factory will in all probability be relocated.

More idioms and phrases containing probability

see in all probability .

Example Sentences

The probability an interval had zero signals was the probability that the first source didn’t emit a signal, 1−p, times the probability the second source didn’t emit a signal, 1−q.

From FiveThirtyEight

In fact, for cancer, historically, the probability of success is about 5 percent.

From Freakonomics

Physicists have algorithms to compute the probabilities of no-loop and one-loop scenarios, but many two-loop collisions bring computers to their knees.

From Quanta Magazine

Simply put, in-market audiences are potential leads that have a high probability of conversion.

From Search Engine Watch

When you were told that your opponent would “play rock or paper with equal probability,” most solvers assumed that meant both probabilities were 50 percent, rather than being equal but less than 50 percent.

From FiveThirtyEight

Probability: 96 percent, unless this spring you finally gave up and ordered central air conditioning, in which case, 15 percent.

From The Daily Beast

A resurrection would be a miracle and as such would defy all “probability.”

From The Daily Beast

The best we can offer is a probability that an earthquake might occur along a fault in a given period of time.

From The Daily Beast

First, how come so many people mistake probability estimates for predictions?

From The Daily Beast

The meaning of a “probability” estimate can be understood by resorting to the last refuge of political metaphors: sports.

From The Daily Beast

At last there appeared some probability of their accomplishing this, after a most curious and truly Mexican fashion.

From Project Gutenberg

But if the Bible was written by men, some of them more or less inspired, then it would not, in all probability be wholly perfect.

From Project Gutenberg

Had justice been ever taken into account, you and I would, in all probability, not have met on the present business.

From Project Gutenberg

We arrive then at this one certain fact, that the flatter the model of a violin the greater the probability of a good fine tone.

From Project Gutenberg

I have not as yet made any inquiry about the probability of getting adventurers for this new concern.

From Project Gutenberg

Related Words

• anticipation
• chance
• contingency
• expectation
• feasibility
• odds
• possibility
• prospect