CBSE Class 11 — Notes, Chapters & Practice Quizzes

Chapter 4: Presentation of Data

Summary

Classified data can be presented in three forms: textual, tabular and diagrammatic. Textual presentation describes the data within the running text and suits small amounts of data, but it forces the reader to go through the whole passage. Tabular presentation arranges data in rows and columns; a well-made table has a table number, title, captions (column headings), stubs (row headings), the body, the unit of measurement, the source and any notes, and the data may be classified qualitatively, quantitatively, temporally or spatially. Diagrammatic presentation is the most attractive and is of three kinds. Geometric diagrams include bar diagrams — simple, multiple and component (sub-divided) — and the pie diagram, in which a circle is divided in proportion to the components after converting values into percentages, each percentage multiplied by 3.6 degrees since the circle has 360 degrees. Frequency diagrams are used for grouped distributions: a histogram uses adjoining rectangles whose area is proportional to class frequency (using frequency density for unequal classes) and gives the mode; a frequency polygon joins the mid-points of their tops; a frequency curve is its smoothed form; and an ogive or cumulative frequency curve, of the "less than" or "more than" type, gives the median where the two curves cross. The arithmetic line graph plots a variable against time to show trends, as with India's exports and imports. Unlike a bar diagram, a histogram leaves no gaps and the width of the bars matters.

Key terms

Important questions

Explore interactively