Import, Tidy, Join & Validate Data

Practice turning raw files into interpretable analytical tables. Study observation units, dictionaries, types, missing codes, reshaping, keys, joins, duplicates, validation and provenance. Prerequisite: beginner R and descriptive statistics. Cases progress from reading a field correctly to diagnosing row multiplication, mixed aggregation levels and misleading cleaning decisions. Worked explanations connect each transformation to the meaning of the resulting data.

Cover: Photo by Rodrigo Santos on Pexels.