Class 9 Maths — Chapter 12: STATISTICS

What you'll learn

• ▸Interpreting Bar Graphs
• ▸Constructing Bar Graphs
• ▸Distinguishing Bar Graphs and Histograms
• ▸Histograms for Uniform Width
• ▸The Principle of Proportional Area in Histograms
• ▸Histograms for Varying Widths

Chapter Summary

--- PAGE 1 --- CHAPTER 12 STATISTICS ______________________________________ 12.1 Graphical Representation of Data The representation of data by tables has already been discussed. Now let us turn our attention to another representation of data, i.e., the graphical representation. It is well said that one picture is better than a thousand words. Usually comparisons among the individual items are best shown by means of graphs. The representation then becomes easier to understand than the actual data. We shall study the following graphical representations in this section. (A) Bar graphs (B) Histograms of uniform width, and of varying widths (C) Frequency polygons (A) Bar Graphs In earlier classes, you have already studied and constructed bar graphs. Here we shall discuss them through a more formal approach. Recall that a bar graph is a pictorial representation of data in which usually bars of uniform width are drawn with equal spacing between them on one axis (say, the x-a…

Practice Questions from this Chapter

Tap "Get Solution" on any question to ask our AI tutor.

1. Compare bar graphs to pie charts. Get Solution →
2. Show real-life data visualization examples. Get Solution →
3. Explain how data predicts future trends. Get Solution →
4. What is a pictorial representation of data where bars of uniform width are drawn with equal spacing between them on one axis? Get Solution →
5. According to the definition of a bar graph, what do the heights of the bars depend on? Get Solution →
6. From the bar graph in Fig. 12.1, how many students were born in the month of November? Get Solution →
7. Which graphical representation is specifically used for continuous class intervals? Get Solution →
8. In the histogram shown in Fig. 12.3, what is indicated by a 'kink' or 'break' on the horizontal axis? Get Solution →

Did you know?

• 💡 The word 'statistics' originated from the Latin for 'state affairs' or 'council of state'.
• 💡 Florence Nightingale used statistical graphs to convince British officials to improve army sanitation.
• 💡 The first bar chart was created in 1786 by William Playfair to show imports and exports.
• 💡 Many famous statisticians were actually mathematicians, like Carl Friedrich Gauss.
• 💡 Maps of stars from ancient Egypt show early attempts at visual data representation.

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