spec: add qq-basic specification

[github-actions]

New Specification: qq-basic

Closes #977

---

specification.md

qq-basic: Basic Q-Q Plot

Description

A Q-Q (Quantile-Quantile) plot compares the distribution of a dataset against a theoretical distribution (typically normal) or another dataset. Points are plotted by matching sample quantiles to theoretical quantiles, with a diagonal reference line indicating perfect distribution match. Deviations from the line reveal distribution characteristics such as skewness, heavy tails, and outliers.

Applications

• Testing normality assumptions before parametric statistical tests (t-tests, ANOVA, regression)
• Identifying distribution characteristics such as skewness and kurtosis in research datasets
• Quality control analysis to verify process measurements follow expected distributions
• Detecting outliers and data quality issues in experimental data

Data

• sample (numeric) - The observed data values to compare against the reference distribution
• Reference: Normal distribution (default) with parameters estimated from sample
• Size: 30-500 observations recommended for meaningful visual comparison

Notes

• Points falling along the diagonal reference line indicate data follows the reference distribution
• Systematic deviations reveal specific distribution characteristics: S-curves indicate skewness, curved ends indicate heavy or light tails
• The 45-degree reference line (y=x) should be clearly visible
• Axis labels should indicate "Theoretical Quantiles" and "Sample Quantiles"

---

Next: Add approved label to the issue to merge this PR.

---

🤖 spec-create workflow