Graphical and Diagrammatic Presentation — Collection, Classification and Presentation of Data, Statistics (Paper-II), SSC CGL

Graphs and Diagrams

Definition: Diagrammatic and graphical presentation displays data visually so comparisons and trends are immediately clear.

Bar diagrams (simple, multiple, sub-divided), pie charts, and pictograms.

Histogram — bars for continuous class intervals.
Frequency polygon — line joining midpoints of histogram tops.
Ogive — cumulative frequency curve (less-than / more-than); their intersection gives the median.

Real-world example: An ogive lets you read off the median and quartiles graphically, without direct calculation.

Example 1. The cumulative frequency curve is known as an:

Example 2. The point where the "less-than" and "more-than" ogives intersect gives the:

Example 3. A frequency polygon is formed by joining the ______ of the tops of histogram bars.

💡 Key concepts & shortcuts

Ogive = cumulative frequency curve; the two ogives intersect at the median.
Histogram bars touch (continuous); bar-chart bars have gaps.
Frequency polygon joins the midpoints of the bar tops.

⚠️ Common mistake

Leaving gaps between histogram bars — continuous data means the bars touch.

Quick-revision notes for Graphical and Diagrammatic Presentation — the must-know points for SSC CGL Tier-I/II.

Diagrams (bar, pie) and graphs (histogram, frequency polygon, ogive) present data visually.
Bar diagrams compare categories; pie charts show parts of a whole.
Histograms represent continuous frequency distributions with adjacent bars.
A frequency polygon joins midpoints of class tops; an ogive is a cumulative frequency curve.
Ogives (less-than and more-than) intersect at the median.
Choose the presentation type based on data nature and the message to convey.

Cover the answer, recall, then check. 6 cards on the must-know Graphical and Diagrammatic Presentation facts for SSC CGL.

Q1. Which chart shows parts of a whole?
A1. A pie chart.

Q2. What is a histogram used for?
A2. Representing a continuous frequency distribution with adjacent bars.

Q3. What is an ogive?
A3. A cumulative frequency curve.

Q4. At what value do the two ogives intersect?
A4. The median.

Q5. What is a frequency polygon?
A5. A line graph joining the midpoints of the tops of the classes.

Q6. How does a histogram differ from a bar diagram?
A6. Histogram bars touch (continuous data); bar-diagram bars have gaps (discrete).