Statistics Blog

Applied statistics tutorials and interactive WebR examples for marketing analytics, published periodically on FlairMI.
Author
Affiliation

Mohammed Ali Sharafuddin

FlairMI

Welcome to FlairMI Statistics Blog

Practical statistics tutorials for marketing and e-commerce analytics. Each post includes:

  • Interactive calculations running directly in your browser (powered by WebR)
  • Real-world business cases from A/B testing, conversion optimization, and revenue analysis
  • Comprehensive explanations with method, assumptions, limitations, and decision frameworks
  • Sample size planning guidance for designing future experiments
  • Reproducible code with detailed statistical computations

All posts use academic-style presentation with no dependency on Python or external servers - just open and run R code in your browser.

New posts are published periodically as teaching notes, worked examples, and interactive statistical explainers are completed.

Welch t-Test vs Equal-Variance t-Test: Comparing Methods

statistics
A/B testing
method comparison
ecommerce

Understand when to use Welch t-test over equal-variance t-test when comparing group means, and learn how variance ratios affect your choice of statistical method.

Oct 25, 2025

Simple Linear Regression: Modeling Revenue from Ad Spend

statistics
regression
marketing analytics
revenue optimization

Estimate the relationship between advertising spend and revenue using ordinary least squares regression, with slope, confidence intervals, R-squared, and diagnostic insights.

Oct 25, 2025

Logistic Regression Basics: Predicting Purchase from Session Count

statistics
logistic regression
conversion optimization
ecommerce

Model purchase probability as a function of on-site sessions using logistic regression, with odds ratios, confidence intervals, and interpretation guidance for binary outcomes.

Oct 25, 2025

Welch t-Test: Comparing Average Order Value Between Groups

statistics
A/B testing
revenue optimization
ecommerce

Compare average order value between control and treatment groups with a Welch t-test and report the mean difference with a confidence interval and effect size.

Jun 24, 2024

Two-Proportion Test: Comparing Conversion Rates Between Variants

statistics
A/B testing
conversion optimization
web analytics

Compare add-to-cart conversion between variant A and variant B with a two-proportion z test and report the difference with a confidence interval and effect size.

Jun 17, 2024

Confidence Interval for a Proportion: Analyzing Add-to-Cart Rate

statistics
A/B testing
conversion optimization
web analytics

Estimate the add to cart rate with a 95% confidence interval, read the margin of error, and decide if KPIs are acceptable. Runnable R/WebR code.

Jun 10, 2024
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