Massafunktion

Massafunktion is a term used in some contexts, particularly in fields like statistics and machine learning, to refer to a probability mass function. A probability mass function, often abbreviated as PMF, is a function that describes the probability of a discrete random variable taking on a specific value. Unlike a probability density function (PDF) which applies to continuous variables, a PMF assigns probabilities to distinct, countable outcomes.

For a discrete random variable X, the probability mass function is denoted by P(X = x) or p(x). This function assigns a probability to each possible value x that X can take. The sum of all probabilities assigned by the PMF over all possible values of X must equal 1. This means that the random variable is certain to take on one of its possible values.

Examples of distributions that have a PMF include the Bernoulli distribution, the binomial distribution, the Poisson distribution, and the geometric distribution. Each of these describes different types of discrete random phenomena and their associated probabilities. Understanding the PMF is crucial for analyzing and predicting the behavior of discrete random variables.