Frequency probability refers to how likely an event is when an experiment is repeated many times.
Frequency probability , also known as frequentist probability , refers to how likely an event is if an experiment is repeated many times . It can be understood as the quotient between the number of favorable cases and the number of possible cases when the number of cases tends to infinity.
The idea of frequency probability is used when working with a very high number of repetitions , thus appreciating the long-term trend. It is important to keep in mind that the assignment of values is always linked to the analysis of multiple iterations: this is why it is common to resort to computer simulations.
The usefulness of frequency probability is often debated by specialists. There are experts who consider that the method is not empirical and that the randomness criteria used are not reliable.
Calculation of frequency probability
To calculate the frequency probability, it is necessary to program the experiment in a system that provides a random iteration. The study of the frequency probability of the phenomenon in question is developed through a table of values .
It is considered that, after a large number of repetitions, the values produced by the experiment are close to the theoretical values . In this way, the frequency probability data are taken to draw conclusions.
The frequency probability can be related, in short, to the relative frequency . This is what is called the quotient between the absolute frequency (the number of times the value appears) and the sample size. It is argued that, with multiple repetitions of the random experiment, the relative frequency approaches the probability of the event.
There are those who maintain that the randomness criteria of frequency probability are not reliable.
Comparison with the classical procedure
Compared to classical probability , we can point out some differences that are often used to negatively criticize frequency:
* classic : used if the results are probable, that is, if a previous study indicates that beyond the possibility of their occurrence, there are indications that support their occurrence;
* frequency : it is measured based on a future estimate or experience, but without evidence that it can really occur;
* classical : the number of favorable results directly influences the study;
* frequency : no behavior is considered definitive throughout the study, but rather they are interpreted forcing the perspective that they cause a particular result.
Von Mises' contributions to the theory of frequency probability
The concept of frequency probability dates back to the mid-19th century, although its formal development took place during the first half of the 1900s by the economist Von Mises , originally from Austria, who proposed two premises to base the theory:
* statistical regularity : although the specific results behave in a somewhat chaotic manner, after subjecting an experiment to a large number of iterations we begin to obtain some patterns of results;
* Probability must be considered objective : Von Mises pointed out that it is a concept that can be measured and based his statement on the fact that random phenomena have some characteristics that make them unique.
Common reviews
Among the specific criticisms that frequent probability has received as an empirical method of calculating probabilities, we can point out the following two statements:
* the concept of limit cannot be considered real : the formula proposed for this concept takes into account that the probability of a fact must become stable by repeating the experiment infinitely. This occurs in cases where N tends to infinity, although it goes without saying that in practice infinite repetition is not possible;
* the sequence cannot be truly random : the need to stabilize the probability mentioned above makes the true randomness of the sequence impossible, since it makes it determined. Furthermore, the random numbers that we can take advantage of in a computerized experiment are not really spontaneous as they would appear in nature.