Prelims · 8 Mental Ability · APPSC Group 2
8.7 Data interpretation and sufficiency notes
7 notes, in reading order.
- 8.7.1Data interpretation: tables and bar graphs
A table or bar graph question is ordinary arithmetic on given numbers: read the right cell, then apply percentage change, "what per cent more", ratio or average — and always divide by the base the question names.
Standard · 6 min · Full course - 8.7.2Data interpretation: pie charts
A pie chart splits a whole of 360° (or 100%) into sectors, so every question reduces to one conversion: 1% = 3.6°, and amount = (angle ÷ 360) × total.
Standard · 5 min · Full course - 8.7.3Data interpretation: line graphs and mixed charts
A line graph shows change over time: the steepest segment is the largest absolute change, but the largest percentage change depends on the starting value — and a fall in a rate is measured in percentage points, not per cent.
Standard · 5 min · Full course - 8.7.4Data sufficiency: arithmetic and reasoning
Data sufficiency asks only whether the statements fix one answer, not what the answer is: test I alone, then II alone, then both together, and stop as soon as the answer is unique.
Standard · 6 min · Full course - 8.7.5Caselet data interpretation: turning a paragraph into a table
A caselet gives the data as a paragraph: draw the table first (one category down, one across, with a Total row and column), fill what is stated, derive the blanks from the totals, and only then read the questions.
Standard · 8 min · Full course - 8.7.6Data interpretation shortcuts: approximation, percentage change and ratios
Most DI arithmetic is a few percentages and divisions: know the fraction–percentage table, split percentages into 10%, 5% and 1% pieces, combine changes with a + b + ab/100, and round only when the options are far apart.
Standard · 7 min · Full course - 8.7.7Missing-data tables and Venn-based data interpretation
In a missing-data table, totals and averages are equations: fill one blank per row or column from them; in a Venn-based set, fill the regions from the centre outwards and use n(A ∪ B) = n(A) + n(B) − n(A ∩ B).
Standard · 8 min · Full course
Practise Data interpretation and sufficiency. Questions with answers explained, from the same topics.
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