Finds the mean of a list of numbers

[Bigbublik]

No description provided.

[ZoomRmc]

Please, read this repo's contribution guidelines. If you had followed them, you'd know that your code doesn't work in its current form - the tests would show it.

1. The file should include a module-level doc-comments, the minimal requirement is the module's name in the first line for auto populating the directory.
2. Examples used in the documentation should be runnableExamples for additional testing. One example is enough, the rest should be tests.
3. The module lacks tests. Follow the minimal example and merged algorithms on how to implement them.
4. nums should be an openArray[SomeNumber]. You'll have to use a loop or std/sequtils.foldl, or import the std/math.sum which works on openArrays.

[dlesnoff]

Sums had a specific module in the stdlib, but were changed to a nimble package. See: nim-lang/Nim#18438
It did not have a mean function though.

Anyway, I would keep a similar version with openArray[SomeFloat] and maybe have a more complex version with openArray[SomeNumber]. I might only keep the second version but I would like to compare both.

I second @ZoomRmc : tests from the documentation could be changed copied under the when isMainModule.
Please, mark your PR as draft if you are not done. The following code indicates so:

when isMainModule:
  discard

[dlesnoff]

Move this under the when isMainModule block.

[dlesnoff]

See my answer in the conversation tab.