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  2. Exponential decay - Wikipedia

    en.wikipedia.org/wiki/Exponential_decay

    Exponential decay is a scalar multiple of the exponential distribution (i.e. the individual lifetime of each object is exponentially distributed), which has a well-known expected value. We can compute it here using integration by parts .

  3. Particle decay - Wikipedia

    en.wikipedia.org/wiki/Particle_decay

    In particle physics, particle decay is the spontaneous process of one unstable subatomic particle transforming into multiple other particles. The particles created in this process (the final state) must each be less massive than the original, although the total mass of the system must be conserved. A particle is unstable if there is at least ...

  4. Kaplan–Meier estimator - Wikipedia

    en.wikipedia.org/wiki/Kaplan–Meier_estimator

    The Kaplan–Meier estimator, [ 1][ 2] also known as the product limit estimator, is a non-parametric statistic used to estimate the survival function from lifetime data. In medical research, it is often used to measure the fraction of patients living for a certain amount of time after treatment. In other fields, Kaplan–Meier estimators may ...

  5. Survival function - Wikipedia

    en.wikipedia.org/wiki/Survival_function

    Survival function. The survival function is a function that gives the probability that a patient, device, or other object of interest will survive past a certain time. [ 1] The survival function is also known as the survivor function[ 2] or reliability function. [ 3] The term reliability function is common in engineering while the term survival ...

  6. Survival analysis - Wikipedia

    en.wikipedia.org/wiki/Survival_analysis

    Survival analysis is a branch of statistics for analyzing the expected duration of time until one event occurs, such as death in biological organisms and failure in mechanical systems. This topic is called reliability theory, reliability analysis or reliability engineering in engineering, duration analysis or duration modelling in economics ...

  7. Accelerated failure time model - Wikipedia

    en.wikipedia.org/wiki/Accelerated_failure_time_model

    Accelerated failure time model. In the statistical area of survival analysis, an accelerated failure time model (AFT model) is a parametric model that provides an alternative to the commonly used proportional hazards models. Whereas a proportional hazards model assumes that the effect of a covariate is to multiply the hazard by some constant ...

  8. Poisson distribution - Wikipedia

    en.wikipedia.org/wiki/Poisson_distribution

    The Poisson distribution is an appropriate model if the following assumptions are true: k is the number of times an event occurs in an interval and k can take values 0, 1, 2, ... . The occurrence of one event does not affect the probability that a second event will occur. That is, events occur independently.

  9. Probability density function - Wikipedia

    en.wikipedia.org/wiki/Probability_density_function

    Unlike a probability, a probability density function can take on values greater than one; for example, the continuous uniform distribution on the interval [0, 1/2] has probability density f(x) = 2 for 0 ≤ x ≤ 1/2 and f(x) = 0 elsewhere. The standard normal distribution has probability density. If a random variable X is given and its ...