Which describes a valid subset in data analysis?

• A. A subset includes only records that meet specified conditions.
• B. A subset includes a random sample of records regardless of conditions.
• C. A subset is the same as the full dataset.
• D. A subset excludes all records.

Answer: (A)

In data analysis, a subset is created by filtering the data to keep only records that meet certain criteria. This means you’re focusing on a group that shares a specific condition, which is exactly what the statement describes when it says the subset includes only records that meet specified conditions. For example, you might filter to keep only customers with purchases over a certain amount or records from a particular region, narrowing the dataset to the relevant portion for analysis.

The other ideas don’t capture that targeted filtering. A random sample can be a subset, but if it’s taken “regardless of conditions,” there are no criteria guiding what to include, so it’s not describing a subset defined by a condition. Treating the full dataset as a subset, or excluding all records to form an empty set, either misses the idea of selective filtering or results in an impractical, empty result.