Parametric Weibull model Sample Clauses

Parametric Weibull model. A model in which a specific probability distribution is assumed for the failure times is known as a parametric model. Parametric survival models from the proportional hazards family are usually fitted on the (log) hazard scale, with covariates included in a linear predictor which is additive on the log hazard scale. There are parametric models for survival times, here I focus on the Weibull model (▇▇▇▇▇ and ▇▇▇▇▇▇▇▇▇▇▇▇ 2005). The Weibull distribution assumes a hazard function of the form: ℎ(𝑡) = 𝜆𝑡𝛾−1 The probability density function for the Weibull distribution is given by 𝑓(𝑡) = 𝜆𝑡𝛾−1exp (−𝜆𝑡𝛾) where 𝛾 = shape parameter and 𝜆= the scale parameter. The survival function is given by 𝑆(𝑡) = exp(−𝜆𝑡𝛾) The Weibull model is utilised in this chapter of work as a parametric comparator for the IG model.