Data Interpretation

What the official syllabus says

Preliminary Examination, General Studies Paper II:

• ... Data interpretation (charts, graphs, tables, data sufficiency etc. — Class X level);

Data interpretation asks a candidate to read information presented as a table, chart or graph and to calculate or compare from it. Data sufficiency asks whether the information given is enough to answer a question, without necessarily calculating the answer. The level is Class X.

Topics in detail

Forms of data

• Tables: single and multiple tables; row and column totals; missing entries.
• Bar charts: simple, multiple (grouped) and stacked bars; horizontal and vertical bars.
• Line graphs: one or more series over time; reading values and trends.
• Pie charts: shares in degrees and in percentages; converting between them (100% = 360°).
• Combined charts: a table with a chart, or two charts on related data.
• Caselets: data given in a paragraph to be organised into a table.
• Venn diagrams and other diagrams presenting counts.

Calculations on data

• Percentage share of a part in a total.
• Percentage increase and decrease between two periods; growth rate.
• Ratios between items, years or groups.
• Averages across years or categories; the average of averages and why it can mislead.
• Differences and totals; the highest and lowest values; the largest change.
• Elementary statistics (Class X): mean, median and mode of a data set.
• Approximation: rounding to compare quickly where options are far apart.

Pie chart conversions

Reading carefully

• Units and scales: thousands, lakhs, crores; percentages versus absolute numbers.
• Axes that do not start at zero; scales that differ between two charts.
• "Percentage" versus "percentage points".
• Whether the question asks for a value, a change, a share or a rank.
• Footnotes and headings that define what a figure means.

Data sufficiency

• The standard format: a question with two statements; whether statement I alone, statement II alone, both together, either alone or neither is sufficient.
• Numerical data sufficiency: equations, ages, ratios, percentages and geometry.
• Logical data sufficiency: arrangements, rankings and relations.
• Avoiding the trap of assuming information not given, and of calculating when only sufficiency is asked.

Method

• Reading the whole chart or table and its headings before the questions.
• Estimating before calculating; keeping fraction-to-percentage equivalents at hand.
• Answering the easiest questions in a set first.

Overlaps

• The arithmetic is that of Basic Numeracy; logical data sufficiency also appears in Logical Reasoning and Analytical Ability.
• Reading economic and social data is also useful for the General Studies III paper's economy topics.