Data interpretation (DI) is where CSAT’s arithmetic meets reading. A table, graph or pie chart is followed by questions on percentage change, share of a total, ratios, averages and trends. The arithmetic is Class X level; what makes DI hard is the clock — and the traps hidden in units, bases and scales. Data sufficiency, also on the syllabus, asks a different question: not “what is the answer?” but “is there enough information to find it?”

This chapter is Prelims-only, and it reuses everything from Percentages, Ratio and Averages. Every data set used here is illustrative and invented for practice — not real statistics.

What this chapter covers

Sub-topic	Key skill
Tables	Row and column totals, percentage change, share of total
Bar and line graphs	Reading scales, comparing absolute and relative change
Pie charts	Degrees ↔ percentages ↔ values
Approximation	Fraction table, rounding, comparing fractions without dividing
Data sufficiency	Testing each statement alone, then together

Start with Data Interpretation: Tables, Graphs and Data Sufficiency, then revise with the quick-revision sheet and attempt the practice set.