Data Is Something That People Make.

Data Can Be Rectangular (Tabular).

Data Can be Structured (Relational).

Data has Rows (Observations) and Columns (Features).

One Row for Each Observation.

One Column for Each Type of Information.

One Value in Every Cell.

Avoid Visual “Data” (i.e. colors in a spreadsheet).

Use Good Null Values.

Save Data in Plain Text Files (CSV or TSV).

Data Can Be Quantitative (Numerical).

• Discrete (integers or whole numbers)
• Continuous (any value, including decimals)

Data Can Be Qualitative (Categorical).

• Ordinal (categories have an order or hierarchy)
• Nominal (categories don’t have an order)