Overview — What DI tests in CAT
Data Interpretation evaluates accuracy with numerical data, ability to read charts, combine information across graphs, approximate quickly, detect traps, and reason under time pressure. Focus on extracting exact values, computing ratios, growth rates, percentage changes, index numbers, and interpreting Venn overlaps.
DI Frameworks & Speed Techniques
- Read axes & units first: Always note scales, units (lakhs, %) and time periods.
- Estimate smartly: Use rounding and compatible numbers; for percentage change use (Δ/old) & shortcut approx.
- Use ratios: Compare using ratios to avoid absolute arithmetic where possible.
- Cross-check answers: Plug back into chart if uncertain.
- Venn approach: compute universe → pairwise → all three using inclusion-exclusion.
Diagrams & How to read them (with SVG examples)
Bar Chart — Monthly Sales (units)
Reading tip: Convert bars to numeric estimates quickly by mapping pixel height to unit scale. Example: If highest bar = 140 units, estimate others proportionally.
Line Graph — Revenue Trend (₹ lakhs)
Reading tip: Slope conveys rate of change — steep uptrend suggests rapid revenue growth; compute percentage change between consecutive points for precision.
Pie Chart — Market Share (%)
Reading tip: Pie slices map to proportions. For quick conversion, 10% ~ 36° of circle. Use percentages directly where given.
Venn Diagram — Overlap of Skills
Reading tip: For Venns, compute exclusive areas then overlaps. Use inclusion-exclusion: |A∪B| = |A| + |B| − |A∩B|.
Worked Examples — step-by-step
- Bar chart quick calc: If May bar is 140 and Jan is 80, percentage increase = (140−80)/80 ×100 = 75%.
- Line graph slope: If revenue Q3=10 and Q4=13 (lakhs), growth = 30% quarter-on-quarter.
- Pie to absolute: If market = ₹200 lakhs and A=40%, A=80 lakhs.
- Venn inclusion-exclusion: If |A|=70, |B|=60, |A∩B|=30 → |A∪B|=100.
50 Practice MCQs — Data Interpretation (Answers highlighted)
Toggle questions and use the charts above as references. These include numeric extraction, percentages, ratios, approximate calculations, and Venn logic.
Q1. From the bar chart above, which month has the highest sales?
Q2. Approximate percentage increase from Jan to Mar (using bar heights)?
Estimate Jan=80, Mar=130 → (130−80)/80=50/80=62.5% ≈ 62%.
Q3. From the line graph, which quarter shows the steepest revenue rise?
Q4. If total market size is 100 units in pie chart, what is sector A's share?
Q5. Venn: If |Analytical|=70, |Comm|=60, overlap=30, what % of union have both?
Overlap is 30 (given).
Q6. If May sales = 140 units and total Jan–Jun = 600 units (approx), what % is May?
Q7. From line graph, revenue Q3 compared to Q2 is:
Q8. If pie slice B=30% and total revenue is ₹500 lakhs, value of B is:
Q9. Venn logic: If 100 people, A=70, B=60, both=30, neither = ?
Union = 70+60−30=100, so neither = 0. Wait, correction: union=100 → neither=0. (Apologies: tiny calculation check.)
Q10. Which month has the least sales (bar chart)?
Q11. Approximate average monthly sales (Jan–Jun) if total ~600 units?
Q12. From line graph, overall trend Q1→Q6 is:
Q13. Pie: If C=30% and A=40%, ratio A:C is:
Q14. If Q4 revenue is 11 and Q5 is 9 (lakhs), Q5 is what % of Q4?
Q15. If May=140 and Jun=60 units, ratio May:Jun =
Q16. From bar chart, which two months combined approx equal May?
Q17. If market total increases by 10% next year, value of B (current ₹150 lakhs) becomes:
Q18. Line graph: which quarter shows a dip compared to previous?
Q19. If total respondents=200, A=120, B=100, both=50 → neither = ?
Union = 120+100−50=170 → neither = 200−170=30.
Q20. From pie, if A increases 5% points and others reduce proportionally, new A =
Q21. If Jan=80 and Apr=110 units, Apr is what % greater than Jan?
Q22. Line: average of Q1–Q6 points roughly equals:
Q23. Pie: If total market ₹200 lakhs, C (30%) = ?
Q24. Venn: If |A∪B|=100, |A|=70, then |B|−|A∩B| = ?
|B|−|A∩B| = |A∪B| − |A| = 100−70 = 30.
Q25. If total sales Jan–Jun = 600 and Mar = 130, Mar share ≈
Q26. If Q2 revenue=12 and Q3=14, growth % =
Q27. Pie: If A=40%, B=30%, C=30% find B−C =
Q28. From bar chart, which month is approx double of Jun?
Q29. Venn: If |A|=50, |B|=40, |A∩B|=10, total=100 → only A = ?
Only A = |A|−|A∩B| = 50−10 = 40.
Q30. If May is 140 and average is 100, May is how many units above average?
Q31. If market grows by 20% and A retains 40% share, A's absolute grows by:
Q32. Line graph: is there a local maximum at Q3?
Q33. Pie: If total=500 and B=30% then B is how many lakhs?
Q34. Bar: sum of Feb and Apr approx equals which month?
Q35. Venn: formula to compute exactly three-way overlap given totals and pairwise overlaps?
Q36. If Jun is 60 units and Jan is 80, Jun is what % less than Jan?
Q37. Pie: Which sector would need rebalancing if one grows disproportionately?
Q38. Bar: approximate difference between Mar and Apr is:
Q39. If total respondents 500, and A only = 120, B only = 80, both=50 → at least one = ?
At least one = only A + only B + both = 120+80+50 = 250.
Q40. Line: between which consecutive quarters is percentage change minimal?
Q41. Pie: If sector shares change but total fixed, what remains constant?
Q42. Bar: which month shows a local minima between two higher months?
Q43. If A=40% of 300, B=30% of 300, difference in absolute = ?
Q44. Venn: If |A∩B| is unknown but |A∪B| and singles known, how to find intersection?
Q45. If average of Jan–Jun increases by removing lowest month value, what happens to average?
Q46. Line: cumulative revenue trend is best approximated by:
Q47. Pie: If one slice halves its share, others increase proportionally — what's the immediate effect on that slice's absolute value if total constant?
Q48. Venn: If only A=40, only B=20, both=10 → total = ?
Q49. Bar: If Feb increased by 25% to become 125, original Feb = ?
Q50. Combined: Using bar + pie, which technique helps most when both charts give partial info?
Practice & Test-day Tips
- Scan charts for units and totals first.
- Use mental math shortcuts: 10% = divide by 10; 5% = half of 10%.
- Practice inclusion-exclusion for Venns until it's second nature.
- When stuck, estimate ranges to eliminate options.