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Excel Statistical Formulas

Organization
cxcscmu
excel-statistical-formulas

Use Excel statistical functions for descriptive analysis including percentiles, weighted calculations, and data summaries.

Overview

Publishercxcscmu
RepositorySkillLearnBench
Skill nameexcel-statistical-formulas
Stars
91
Forks
7
Bundled files
Instructions only
LicenseMIT
Links
  • Markdown instructions

    A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.

  • Works with any LLM

    AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.

  • Self-contained

    Everything the model needs lives in the instructions — no extra files to sync.

  • Open source

    Published by cxcscmu on GitHub. Read the source before you install it.

Installation

Install the Excel Statistical Formulas AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

1

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

  1. Open the app and go to Plugins → Skills.
  2. Choose "Install from GitHub".
  3. Paste the skill folder URL below and confirm.
    https://github.com/cxcscmu/SkillLearnBench/tree/main/skills/b1-one-shot-claude-haiku-4-5/weighted-gdp-calculation/excel-statistical-formulas
  4. Enable the skill in any chat where you want it available.
Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.
2

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills
git clone --depth 1 https://github.com/cxcscmu/SkillLearnBench.git /tmp/SkillLearnBench
mkdir -p .claude/skills
cp -r /tmp/SkillLearnBench/skills/b1-one-shot-claude-haiku-4-5/weighted-gdp-calculation/excel-statistical-formulas .claude/skills/excel-statistical-formulas
Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Excel Statistical Formulas in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Excel Statistical Formulas on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Excel Statistical Formulas is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

  • Loaded only when it is needed

    The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.

  • Switch models mid-chat

    Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Excel Statistical Formulas

Overview

Statistical functions in Excel calculate measures like mean, median, percentiles, and enable weighted calculations for economic data analysis.

Core Statistical Functions

Basic Descriptive Statistics

MIN - Returns the smallest value

=MIN(range)
=MIN(H35:L40)

MAX - Returns the largest value

=MAX(range)
=MAX(H35:L40)

MEDIAN - Returns the middle value

=MEDIAN(range)
=MEDIAN(H35:L40)

AVERAGE - Returns the arithmetic mean

=AVERAGE(range)
=AVERAGE(H35:L40)

Percentile Functions

PERCENTILE - Returns the kth percentile of a dataset

=PERCENTILE(range, k)

Where k is a decimal (0.25 for 25th percentile, 0.75 for 75th percentile)

Examples:

25th Percentile:  =PERCENTILE(H35:L40, 0.25)
75th Percentile:  =PERCENTILE(H35:L40, 0.75)

PERCENTILE.INC vs PERCENTILE.EXC:

  • PERCENTILE.INC: Inclusive method (older PERCENTILE function)
  • PERCENTILE.EXC: Exclusive method (newer, statistical best practice)

Weighted Mean Calculation

SUMPRODUCT for Weighted Mean

The SUMPRODUCT function multiplies corresponding elements in arrays and returns the sum of products.

Syntax:

=SUMPRODUCT(array1, array2, ...)

Weighted Mean Formula:

=SUMPRODUCT(values_array, weights_array) / SUM(weights_array)

Example: Weighted Mean of Net Exports by GDP Weight

=SUMPRODUCT(G35:G40, GDP_weights) / SUM(GDP_weights)

How it works:

  1. Multiply each value by its corresponding weight
  2. Sum all products
  3. Divide by sum of weights

Handling Multiple Columns

For data across multiple columns (like multiple years), you may need to:

  1. Flatten the data into single rows/columns, or
  2. Use array formulas with SUMPRODUCT

Example with multiple criteria:

=SUMPRODUCT((range1=criteria1)*(range2=criteria2)*values) / SUMPRODUCT((range1=criteria1)*(range2=criteria2)*weights)

Percentage Calculations

Converting to Percentage Display

Excel stores percentages as decimals (0.123 = 12.3%).

To display as percentage (12.3 instead of 0.123):

=formula_result * 100

To round to one decimal place:

=ROUND(formula_result * 100, 1)

Combined example:

=ROUND(SUMPRODUCT(values, weights) / SUM(weights) * 100, 1)

Practical Example: GCC Net Exports Analysis

Step 1: Calculate Net Exports Percentage

=Net_Exports / GDP * 100

Step 2: Calculate Statistics

Min:       =MIN(values) * 100
Max:       =MAX(values) * 100
Median:    =MEDIAN(values) * 100
Mean:      =AVERAGE(values) * 100
25th %ile: =PERCENTILE(values, 0.25) * 100
75th %ile: =PERCENTILE(values, 0.75) * 100

Step 3: Weighted Mean

=SUMPRODUCT(values, weights) / SUM(weights) * 100

Where:

  • values: Net exports as % of GDP
  • weights: GDP figures (or country weights)

Rounding Best Practices

ROUND function:

=ROUND(number, num_digits)
  • num_digits = 1 for one decimal place
  • num_digits = 0 for whole numbers
  • num_digits = -1 for tens place

Example:

=ROUND(12.345 * 100, 1)  → 1234.5
=ROUND(0.12345 * 100, 1) → 12.3

Performance Considerations

  1. SUMPRODUCT with conditions: More flexible than SUMIFS, but slower on large datasets
  2. Array formulas: Use where needed but consider calculation time
  3. Volatile functions: MIN, MAX, PERCENTILE may recalculate frequently

Tips for Economic Data

  1. Handling missing data: Use IFERROR with statistical functions

    =IFERROR(PERCENTILE(range, 0.25), "N/A")
  2. Weighted by GDP: When calculating regional averages, weight by GDP size

    =SUMPRODUCT(country_values, country_gdp) / SUM(country_gdp)
  3. Multi-year analysis: Calculate across years while maintaining criteria

  4. Sensitivity: Test with subsets to validate formula logic

Frequently asked questions

What does the Excel Statistical Formulas AI skill do?

Use Excel statistical functions for descriptive analysis including percentiles, weighted calculations, and data summaries.

Why use Excel Statistical Formulas on TypingMind?

Because you install it once and use it with any model. Excel Statistical Formulas is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Excel Statistical Formulas in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/cxcscmu/SkillLearnBench/tree/main/skills/b1-one-shot-claude-haiku-4-5/weighted-gdp-calculation/excel-statistical-formulas. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Excel Statistical Formulas?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Excel Statistical Formulas?

As many as you like. As long as a model supports skills, you can use Excel Statistical Formulas with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Excel Statistical Formulas AI skill free?

Yes. It is published on GitHub by cxcscmu under the MIT license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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