Graphical Analysis & Data Interpretation Short class notes for CSIR-UGC NET/JRF/Ph.D. (Part A – General Aptitude)

 

Graphical Analysis & Data Interpretation

Short class notes for CSIR-UGC NET/JRF/Ph.D. (Part A – General Aptitude)

1. Question formats you’ll face

• Bar/line/pie charts: read absolute, percentage and ratio changes.

• Tabulated data: compute row/column totals, averages, percentage share.

• Mixed graphs: compare two years/branches/companies shown in paired bar-sets.

• Quantitative comparison: decide whether Quantity A > B, A < B, A = B or “cannot be determined”.
  Past ten papers contain 6–8 marks from these patterns.

2. Five universal steps to crack any DI set

1. Glance → spot axes, units and scales (beware bars that don’t start from zero).

2. Pre-compute grand totals if the set will reuse them.

3. Mark required operations: Δ (difference), %∆ (percentage change), ratio, average.

4. Approximate first; refine only if options are close (saves ~40 s per item).

5. Sanity-check—extreme values should match the visual trend.

3. Must-memorise micro-formulae

Situation	Quick rule	Example
% increase	$\frac{\text{new−old}}{\text{old}}×100$	From 35 t to 50 t ⇒ 42.9%
Average	$\frac{\Sigma x}{n}$	6 branches sell 480k books ⇒ 80k avg.
Compound Δ (bar graph year-on-year)	Add successive % changes: 20% rise then 10% fall = $20−10−2 = 8$% net	—
Pie-slice value	$\frac{\theta}{360}×\text{total}$	72° of 18 M ₹ ⇒ 3.6 M ₹
Ratio shortcut	Write values in simplest integer ratio	150 : 205 → 30 : 41

4. Graph-specific tricks

1. Bar graphs

   • Draw an imaginary grid—each cell = 10 units helps eyeball differences quickly.

   • For “maximum percentage rise”, compute only years where absolute rise exists; skip falls.

2. Line graphs

   • Steeper slope ≈ larger change; use when options are widely separated.

   • If two lines intersect, values are equal at that point.

3. Pie charts

   • Convert required sector to degrees quickly: 10% = 36°, 25% = 90°, 33⅓ % = 120°.

   • For “arrange funds shortage”, difference ×100 / existing share gives % hike needed.

4. Tables

   • Circle columns/rows actually referenced in questions—avoids mis-reading big tables.

   • For “least/most efficient”, compute per-unit metric once; reuse for all items.

5. Two solved prototypes

Prototype A – Paired bar set
Books sold (000) by branches B1–B6 in 2000 & 2001.
Q: % sales of B6 (two-year total) to B3 total?

• B6 = 70+80 =150; B3 = 95+110 =205 ⇒ $150/205×100 ≈ 73.2\%$.

Prototype B – Pie chart
NHAI funding pie (total ₹57,600 cr).
Q: Central angle for Market borrowing (₹29,952 cr)?
$29,952/57,600×360 ≈ 187.2°$.

6. Practice drill (DIY)

1. Draw a pie of five equal sectors; if Sector A = 540 students, find total.

2. Using any newspaper graphic, frame three ‘percentage change’ questions and solve within 4 minutes.

3. Re-work bar-graph sets from 2019-24 CSIR exams; target ≥80% accuracy.

7. Recommended 

•  day-wise DI & graph schedule + mock sets.

•  bar/line/pie concept notes & timed quizzes.

• 30 fully-solved DI examples (tables, bars, pies, mixed).

Consistent practice with these techniques will lift your Graphical Analysis & Data Interpretation score from a typical 55% to 80%+—an easy 12-15 marks edge in the overall paper.