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Add Wilcoxon Distribution

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#293 2 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
38/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
fsharp
Domain
data

Research direction

Start by comparing src/FSharp.Stats/Distributions/Continuous/Normal.fs with other distribution implementations, then read the original publication and the Rwilcox reference. Add Wilcoxon.fs under Distributions/Continuous and unit tests modeled on the exponential distribution tests in tests/FSharp.Stats.Tests/DistributionsContinuous.fs; run ./build runtests to verify the calculations.

Written by the indexing model from the issue text.

Description

Difficulty: Advanced FsLab Hackathon 2023 Status: Available
Description

The signed rank test currently is only an approximation for large values (see https://github.com/fslaborg/FSharp.Stats/pull/182#discussion_r908169551)
There is a valid wilcoxon distribution that is quite expensive to calculate. Nevertheless it is required to calculate exact u test results, and should be implemented:

Citation from #213

To perform a valid u test it is required to implement the Wilcoxon distribution. Is should be added as individual source file within Distributions/Continuous. You can copy the Distributions/Continuous/Normal.fs and replace all fields with its corresponding entries for the Wilcoxon distribution.

References
Pointers
  • suggested workflow:
    • check out other distribution implementations and the original publication
    • copy a existing source file (e.g. Normal.fs), rename it to Wilcoxon.fs and replace all members.
      • this may be harder as you would imagine, but even if not all members are implemented, it would help us bringing FSharp.Stats a step further
    • optional: add unit tests
Hints (click to expand if you need additional pointers)

A final PR should contain the source file as well as unit tests to verify the correct results of the calculations. But even if some functions are missing, you can file a PR and mention what has to be added and where the problems are. For appropriate unit tests you can check out exponential distribution unit tests.

Dominant language
F#
Stars
228
Forks
58
Avg merge
2d 7h
Merged PRs (30d)
1

Getting set up

First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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