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Hauptverfasser: Hentschel, Brian, Haas, Peter J., Tian, Yuanyuan
Format: Preprint
Veröffentlicht: 2021
Schlagworte:
Online-Zugang:https://arxiv.org/abs/2105.10809
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author Hentschel, Brian
Haas, Peter J.
Tian, Yuanyuan
author_facet Hentschel, Brian
Haas, Peter J.
Tian, Yuanyuan
contents Probability proportional to size (PPS) sampling schemes with a target sample size aim to produce a sample comprising a specified number $n$ of items while ensuring that each item in the population appears in the sample with a probability proportional to its specified "weight" (also called its "size"). These two objectives, however, cannot always be achieved simultaneously. Existing PPS schemes prioritize control of the sample size, violating the PPS property if necessary. We provide a new PPS scheme that allows a different trade-off: our method enforces the PPS property at all times while ensuring that the sample size never exceeds the target value $n$. The sample size is exactly equal to $n$ if possible, and otherwise has maximal expected value and minimal variance. Thus we bound the sample size, thereby avoiding storage overflows and helping to control the time required for analytics over the sample, while allowing the user complete control over the sample contents. The method is both simple to implement and efficient, being a one-pass streaming algorithm with an amortized processing time of $O(1)$ per item.
format Preprint
id arxiv_https___arxiv_org_abs_2105_10809
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Exact PPS Sampling with Bounded Sample Size
Hentschel, Brian
Haas, Peter J.
Tian, Yuanyuan
Methodology
Probability proportional to size (PPS) sampling schemes with a target sample size aim to produce a sample comprising a specified number $n$ of items while ensuring that each item in the population appears in the sample with a probability proportional to its specified "weight" (also called its "size"). These two objectives, however, cannot always be achieved simultaneously. Existing PPS schemes prioritize control of the sample size, violating the PPS property if necessary. We provide a new PPS scheme that allows a different trade-off: our method enforces the PPS property at all times while ensuring that the sample size never exceeds the target value $n$. The sample size is exactly equal to $n$ if possible, and otherwise has maximal expected value and minimal variance. Thus we bound the sample size, thereby avoiding storage overflows and helping to control the time required for analytics over the sample, while allowing the user complete control over the sample contents. The method is both simple to implement and efficient, being a one-pass streaming algorithm with an amortized processing time of $O(1)$ per item.
title Exact PPS Sampling with Bounded Sample Size
topic Methodology
url https://arxiv.org/abs/2105.10809