Add Greek (el) R category and book: "Εισαγωγή στον προγραμματισμό και στη στατιστική ανάλυση με R"

[Maria-Papa]

What does this PR do?

Add resource(s)

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Description

This Greek-language undergraduate textbook offers a comprehensive introduction to programming and statistical analysis using the R language. It begins with the fundamentals of R syntax and data structures—vectors, matrices, data frames, and lists—before progressing to control flow with loops and conditional statements. The book emphasizes practical data handling, user interaction, and visualization techniques, culminating in the creation of functions and algorithms tailored to statistical applications. With clear examples and structured chapters, it’s designed to help students in statistics and data science build a solid foundation in computational thinking and statistical modeling.

Why is this valuable (or not)?

This resource is valuable because it bridges the gap between programming literacy and statistical reasoning, two essential skills in modern data-driven disciplines. R is widely used in academia and industry for statistical computing, and this book provides a localized, accessible path for Greek-speaking learners to master it. Its free availability under a Creative Commons license makes it an ideal addition to open educational repositories, supporting equitable access to high-quality learning materials in STEM fields.

How do we know it's really free?

The book is published by Kallipos, a government-funded open academic publishing platform in Greece. It is distributed under the Creative Commons BY-NC-SA 3.0 license, which permits free access and non-commercial redistribution with attribution.

For book lists, is it a book? For course lists, is it a course? etc.

It is a book.

Checklist:

• Search for duplicates.
• Include author(s) and platform where appropriate.
• Put lists in alphabetical order, correct spacing.
• Add needed indications (PDF, access notes, under construction).
• Used an informative name for this pull request.

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[Maria-Papa]

I noticed the CONTRIBUTING file doesn’t mention formatting guidelines for resources with multiple authors. Could you please review my formatting to confirm it aligns with your expectations?

If it looks good, I suggest opening an issue to clarify how multi-author entries should be handled in future contributions.