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English Medium / Class 7 / Math / Statistics - Sub divided bar graph, Percentage bar graph (Only introduction)
Statistics - Sub divided bar graph, Percentage bar graph (Only introduction)
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Introduction

Statistics involves collecting, analyzing, and presenting data. Visual representation through graphs makes complex data easy to understand at a glance. Whether comparing sports stats or budgeting, graphs provide a clear picture of numbers.

 

 

 

Understanding data distribution through visual charts.

Sub-topics

1. Joint Bar Graph

This graph displays two or more sets of data side-by-side for the same category. It is ideal for direct comparison.

Examples

Example 1: Sales Comparison (Real-life)
Compare the sales of Laptop vs. Desktop in a store for Jan, Feb, and March.
Two bars (Laptop and Desktop) will be placed next to each other for each month.
Tricky Example
Can a joint bar graph show 3 or more variables for one category?
Yes, for example, comparing marks of English, Math, and Science for 5 different students simultaneously.

2. Sub-divided Bar Graph

A single bar is divided into different parts to represent components of a whole. The total height of the bar shows the sum.

Examples

Example 1: Family Savings (Real-life)
A family earns 10,000. They spend 7,000 and save 3,000. Draw a sub-divided bar.
One bar of height 10,000 divided into two colored sections (7,000 and 3,000).

3. Percentage Bar Graph

In this graph, all bars are of equal height (100 units). It shows the proportion of each part relative to the total.

Examples

Example 1: Literacy Rate (Real-life)
Compare the literacy rate of two villages with different populations (500 and 2000).
Both bars will be 100% high, allowing a fair comparison of the literacy "ratio" regardless of population size.

4. Pie Chart

A circular graph divided into sectors, where each sector represents a proportion of the whole 360°.

Examples

Example 1: School Budget (Real-life)
Showing how a school spends its funds on Sports, Library, and Repairs.
A circle where the biggest slice represents the highest expense.

Tricks and Shortcuts

* In Percentage Graphs: (Part / Total) × 100 is your magic formula.
* For Pie Charts: (Value / Total) × 360 gives you the angle in degrees.

Common Mistakes

* Using different widths for bars; all bars must have equal width.
* Forgetting to write the scale (e.g., 1 cm = 10 units) on the Y-axis.

Practice Questions

Easy Questions

  1. Draw a bar graph showing the favorite fruits of 10 students.
  2. What is the total sum of angles in a pie chart?
  3. If a bar is divided into two parts, what kind of graph is it? (Tricky)

Medium Questions

  1. A student scored 40 out of 50 in Math. What percentage will this be in a percentage bar graph?
  2. If a sector in a pie chart is 90°, what fraction of the whole does it represent?
  3. Compare the number of bicycles and cars in a parking lot using a joint bar graph. (Real-life)

Hard Questions

  1. When comparing the growth of two companies with very different starting capitals, why is a percentage bar graph better than a sub-divided one? (Tricky)
  2. A company has 30% profit. Calculate the angle for this in a pie chart. (Real-life)
  3. Draw a sub-divided bar graph where the total is 200 and it consists of three parts in the ratio 2:3:5.

Revision Summary

Graphs transform numbers into stories. Use joint bars for comparison, sub-divided bars for totals, percentage bars for proportions, and pie charts for parts of a whole.

What is the main difference between a Subdivided Bar Graph and a Percentage Bar Graph?

A
    
In a percentage bar graph, the height of all bars is equal, whereas in a subdivided bar graph, it is not
B
    
Comparison is not possible in a subdivided bar graph.
C
    
There is no difference between the two.
D
    
A percentage bar graph is always circular.
Explaination



What percentage of total expenditure do 'food' and 'rent' together cover?  

A
    
50%
B
    
55%
C
    
60%
D
    
65%
Explaination
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