Data analysis questions require you to extract relevant information, connect quantities, and make a justified calculation or decision. The common formats are caselets, missing-data questions, and data sufficiency questions.

Core calculations

• Total: add all relevant values.
• Average: total / number of observations.
• Percentage: part / whole x 100.
• Percentage change: (new value - old value) / old value x 100.
• Ratio: write comparable quantities in the same unit and simplify.

Caselets

A caselet is a short paragraph containing data, conditions, and relationships instead of a chart. Convert its statements into a small table, list, equation, or diagram before calculating.

• Separate fixed values, totals, and percentage or ratio relationships.
• Use only facts relevant to the question; extra details may be included as distractors.
• Track the base value for every percentage carefully.

Missing data problems

In missing-data questions, one or more values are absent from a table or chart. Reconstruct them using totals, averages, percentages, ratios, or relationships given elsewhere in the data.

• Missing value = total - sum of known values.
• Missing value = average x count - sum of known values.
• Use row totals and column totals independently as a cross-check.
• Do not assume a value unless the relationship makes it unique.

Data sufficiency

Data sufficiency asks whether the statements provide enough information to answer a question. The goal is not always to calculate the answer; decide whether it can be determined uniquely.

• Test statement 1 alone and statement 2 alone before combining them.
• A statement is sufficient only if it produces one definite answer.
• Two statements together are sufficient when each alone is insufficient but their combination determines the answer.
• Use counterexamples to prove that a statement permits more than one answer.

Common answer conventions

• Statement 1 alone is sufficient.
• Statement 2 alone is sufficient.
• Both statements together are sufficient, but neither alone is sufficient.
• Either statement alone is sufficient.
• Even both statements together are insufficient.

How to solve questions

1. Read the question first so you know exactly what must be found.
2. Organise the given information into values, totals, rates, ratios, or equations.
3. Use the simplest relationship that connects the required data.
4. For data sufficiency, test each statement separately before combining them.
5. Check units, base values, and whether the answer is unique.