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Related Experiment Video

Updated: Jun 2, 2026

Sampling Soils in a Heterogeneous Research Plot

Sampling Soils in a Heterogeneous Research Plot

Published on: January 7, 2019

Optimal sample sizes for Welch's test under various allocation and cost considerations.

Show-Li Jan¹, Gwowen Shieh

¹Department of Applied Mathematics, Chung Yuan Christian University, Chungli, Taiwan, 32023, Republic of China. sljan@math.cycu.edu.tw

Behavior Research Methods

|April 23, 2011

Summary

Determining adequate statistical power requires careful sample size planning. This study introduces practical methods for optimizing sample size, considering budget and participant allocation constraints for Welch's t-test.

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Area of Science:

Statistics
Biostatistics
Research Methodology

Background:

Sample size determination is crucial for statistical power in research.
Conventional methods often neglect budget and participant allocation constraints.
Integrating cost and allocation schemes complicates, yet enhances, practical sample size planning.

Purpose of the Study:

To present exact techniques for optimizing sample size determination.
To address Welch's t-test for the difference between two means.
To incorporate various design, allocation, and cost considerations.

Main Methods:

Developed exact techniques for sample size optimization.
Considered allocation schemes where group size ratios are given or one size is specified.
Addressed cost implications for maximizing power within a fixed budget or achieving power at minimal cost.

Main Results:

Proposed methods offer practical alternatives to conventional sample size procedures.
Techniques are applicable under different group size constraints and cost scenarios.
Implemented methods are available via R and SAS programs.

Conclusions:

The presented methods provide a more practical approach to sample size planning.
Optimizing sample size with cost and allocation considerations enhances study efficiency.
These techniques facilitate robust statistical power under realistic research constraints.