Warm up and exercises from 1.2.5; 1.4.3; 1.5.5; and 1.6.1 of R for Data Science Ch 1, prepared by Quran Green.

Decision trees can be created intuitively in R using the `rdecision` package. The creation follows a logic that is easy to follow. The yield is a visual tree output, in addition to the expected costs and benefits for each alternative required for ICER calculation.

End-to-end market basket analysis of Online Retail II in R: robust cleaning, StockCode-based transactions, Apriori/Eclat itemset mining, actionable cross-sell rule curation, visual diagnostics, and a fully reproducible R Markdown workflow with environment metadata for transparent, decision-ready insights.