Standard Deviation Calculator

WHAT IT DOES

Standard Deviation Calculator is a floating panel that computes comprehensive statistical summaries for any dataset. Enter a list of numbers separated by commas, spaces, or newlines—the panel instantly calculates population and sample standard deviation, population and sample variance, mean, count, sum, minimum, maximum, range, and median. A frequency distribution table shows how values are distributed, and a visual bar or sparkline representation provides an at‑a‑glance view of the data's spread. You can add numbers one by one or paste a full list, and the panel remembers your dataset across sessions. You can insert the standard deviation, mean, or any summary statistic directly into any editable field on the page (input, textarea, or contenteditable) with one click, or copy all results to your clipboard. Perfect for students analyzing experimental data, researchers performing statistical summaries, quality control professionals monitoring process variation, or anyone needing quick statistical analysis without opening a spreadsheet.

WHERE IT RUNS

The panel overlays any website that loads the BotGentz extension—whether you're on a research paper, a data analysis dashboard, a spreadsheet, a note‑taking app, or any other web page. It works on all modern Chromium‑based browsers (Chrome, Edge, Brave, Arc) and Firefox. The script injects a self‑contained UI element that does not interfere with the host page's layout, styles, or JavaScript execution. It runs client‑side only, with no external API calls or cloud dependencies.

HOW TO USE

After installing the free BotGentz extension, visit any page and click the extension icon to activate the panel. The first time you use Standard Deviation Calculator, it will appear as a draggable widget near the bottom‑right corner of your viewport, with a sample dataset pre‑filled. To analyze your data:

- Enter numbers in the input field, separated by commas, spaces, or newlines (e.g., "10, 12, 23, 23, 16, 23, 21, 16").

- The panel automatically parses your input and updates all statistics live as you type.

- Click "Add Single Value" to append a number to the dataset without retyping everything.

- Click "Clear All" to reset the dataset.

The panel displays the standard deviation (both population and sample), variance, mean, median, count, sum, min, max, and range. A frequency distribution is shown as a text summary, and a sparkline bar chart visualizes the data's distribution. To use the results:

- Click "Insert Standard Deviation" to paste the population standard deviation into the focused editable field.

- Click "Insert Mean" to paste the mean into the focused field.

- Click "Copy All Results" to copy all statistics to your clipboard.

The panel remembers your dataset across sessions via GM_setValue, so you can close the panel and resume later.

PRECISION STATISTICAL ENGINE WITH BATCH PROCESSING AND VISUAL SPARKLINE

Unlike simple calculators that compute only basic averages, this panel uses a precision statistical engine that computes both population and sample statistics using numerically stable algorithms. The engine parses input via a flexible tokenizer that splits on commas, spaces, semicolons, and newlines, converting each token to a float with proper error handling. It then computes the sum, mean, and sum of squared deviations in a single pass using the Welford online algorithm (Knuth's method) to avoid catastrophic cancellation when summing large numbers. This approach maintains numerical precision even with datasets containing values that vary widely in magnitude. The variance and standard deviation are computed both as population (dividing by n) and sample (dividing by n‑1) estimates, giving users both measures. The median is computed by sorting a copy of the data using an efficient native sort. The sparkline visualizer aggregates the data into up to 50 bars for performance, scaling the bar heights proportionally to the data range and rendering them as inline div elements with minimal overhead. The frequency distribution is presented as a compact table showing value counts, helping users understand data density at a glance.

THE PANEL

- Drag: Click and hold the panel's header bar to move it anywhere on the screen.

- Per‑site position: The panel stores its last position separately for each domain (e.g., different positions for Google Sheets vs. Jupyter Notebook) using the browser's localStorage, keyed by hostname.

- Snap: When dragged near any edge of the viewport, the panel snaps to that edge with a 16px margin for a clean, docked feel.

- Collapse: Click the "−" button in the header to collapse the panel to a compact title bar, preserving all current values. Click "+" to expand it back.

- Resize: Drag the bottom‑right corner handle to resize the panel from 280px to 600px wide and 200px to 500px tall; the layout adapts responsively.

- Escape: Press the Escape key while the panel is focused to close it entirely (you can reopen it from the extension toolbar).

PLEASE NOTE

This script requires the free BotGentz extension to run—it is not a standalone bookmarklet or user script. Websites frequently update their DOM structures and security policies; while we strive to keep the panel functional across thousands of sites, occasional updates may be needed. The calculator performs all operations entirely in your browser—no data is sent to any server, and no cookies or tracking identifiers are used. Your dataset and computed statistics remain private to your local session and are persisted only via GM_setValue (the extension's local storage) for convenience, not shared across devices or sessions. The sparkline visualization is a simplified representation and should not be used for precise data interpretation. For critical statistical analysis, always verify results with dedicated statistical software.