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Chapter 4: Presentation of Data

Data presentation is the art of displaying collected and organized data in an attractive, easily readable, and understandable manner.

Tabular Presentation of Data

Tabulation involves presenting numerical data systematically in rows and columns. A well-constructed table contains a Table Number, Title, Headnotes, Stubs (row headings), Captions (column headings), Body, Footnotes, and Source.

Diagrammatic Presentation of Data

Diagrams are visual representations that make complex data immediately comprehensible.

1. Geometric Forms: Bar Diagrams and Pie Diagrams

Bar Diagrams are graphs composed of a series of bars of equal width. The height or length of the bars determines the value.

0 20 40 60 80 2020 2021 2022 2023 2024 Production Over Years (in '000 tonnes)

Pie Diagrams represent data in a circle, where the area of each slice is proportional to the quantity it represents. Total angle is 360°.

Food (40%) Rent (30%) Clothing (20%) Saving (10%) Household Expenditure Distribution

2. Frequency Diagrams: Histogram, Polygon, and Ogive

A Histogram is a two-dimensional diagram. It is a set of contiguous rectangles where class intervals are represented on the X-axis and frequencies on the Y-axis.

0 10 20 30 40 50 Frequency Distribution Histogram

A Frequency Polygon is formed by joining the mid-points of the tops of all rectangles in a histogram by straight lines. It can also be drawn independently by plotting the frequencies against the mid-values of the class intervals.

0 5 15 25 35 45 55 Frequency Polygon Freq

An Ogive or Cumulative Frequency Curve is constructed by plotting cumulative frequencies against the respective class limits.

Median 0 Class Boundaries c.f. Less Than Ogive More Than Ogive Ogive (Cumulative Frequency Curve)

3. Arithmetic Line Graphs (Time Series Graph)

Used primarily to represent data recorded over time, such as national income or population over decades.

0 10 20 30 40 2019 2020 2021 2022 2023 Growth (Time Series Graph)

Competency-Based Questions

Application-Based Question

Q1. A school wants to analyze the pass percentage of its Grade 11 students across five years. Which geometric form of a diagram would most visibly demonstrate the comparison, and why?

Answer: A Multiple Bar Diagram or a simple Bar Diagram would most visibly demonstrate this comparison. Since time series data across discrete intervals (years) is involved, placing bars side-by-side easily reveals trends and variations in the pass percentage over the years.

Evaluation Question

Q2. Identify the diagram used to graphically locate the Median and Mode of a frequency distribution.

Answer:

  • The Histogram can be used to graphically locate the Mode (by joining the top corners of the highest rectangle to the corners of the adjacent rectangles).
  • The Ogive (Cumulative Frequency Curve) is used to locate the Median (by plotting the less than ogive and more than ogive; their intersection point corresponds to the median on the X-axis).