An introduction to rejection sampling

An introduction to rejection sampling

🎙 Ben Lambert 👥 148K 📅 May 15, 2018 ⏱ 10 min 👁 59K 📄 tutorial 🧭 2026-08-17
Available in: English (current) Français

Keywords

rejection samplingMonte Carloprobability densitysimulationBayesian

Summary

This video provides an introductory tutorial on rejection sampling, a method for generating independent samples from a probability density function (PDF), even when the PDF is unnormalized. The presenter, Ben Lambert, uses the example of sampling from an exponential distribution with rate parameter 1 to illustrate the algorithm. He explains that rejection sampling involves generating a candidate x uniformly from a bounded interval and a candidate y uniformly from [0,1], then accepting x if y is less than the PDF value at x, otherwise rejecting it. He demonstrates the process using Mathematica simulations, showing how accepted points accumulate under the PDF curve and how the histogram of accepted x values approximates the target distribution. He also shows an example with an unnormalized trigonometric density, highlighting that rejection sampling can handle cases where the normalizing constant is unknown. The video concludes by noting that rejection sampling is inefficient, especially in higher dimensions, as many points are rejected. The tutorial is clear and accessible, with visual aids, and is part of a lecture course on Bayesian statistics.

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Critical Evaluation

Value of the Information & Strength of the Argument

The video provides a solid introduction to rejection sampling, explaining the algorithm step-by-step with clear visual demonstrations. The argumentation is sound: the presenter correctly notes that having an analytic form of the PDF does not automatically allow independent sampling, and he demonstrates the method’s utility for unnormalized densities. The use of simulations effectively illustrates the concept and shows the convergence of the sample histogram to the target distribution. The explanation of inefficiency is accurate, though it could have been more quantitative (e.g., acceptance rate). Overall, the information is valuable for learners, and the reasoning is coherent.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is adequate for an introductory tutorial. The method is standard and correctly explained. The presenter references his own textbook, ‘A Student’s Guide to Bayesian Statistics’, and provides links to his website and playlist, but no primary research sources are cited. The title accurately reflects the content. The video is part of a lecture course, so it is educational rather than presenting new research. The description includes links to additional resources, which are useful for further study.

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Title / Content Match

The title accurately reflects the content, which is a basic introduction to rejection sampling.

Quality & Reliability

8/10

Clear explanation of a standard statistical technique, with visual demonstrations and references to a textbook. No citations to primary sources, but the method is well-established.

Key Moments

Cited Sources

Concurring Sources

Contribution & Novelties

The video provides a clear and accessible introduction to rejection sampling, with visual demonstrations that help intuition. It is not novel research but serves as a pedagogical resource. For further exploration, one can look into related Monte Carlo methods such as importance sampling, Metropolis-Hastings, and the concept of acceptance-rejection sampling in higher dimensions. These are standard topics in computational statistics.

Pour aller plus loin :

96 words

Radar Profile

The radar profile shows high scores in quality of information and reliability, with moderate scores in quantity and technical level. This indicates a well-explained tutorial that is reliable but not highly technical or information-dense.

Reliability 8/10