6th Class Mathematics Data Handling

Data Handling

In this chapter we will learn about pictograph and bar graph.

Data

Data is a collection of facts, such as numbers, observations, words or even description things.

Observation

Each numerical figure in a data is called observation.

Frequency

The number of times a particular observation occurs is called its frequency.

Statistical Graph

The information provided by a numerical frequency distribution is easy to understand when we represent it in terms of diagrams or graphs.

To represent statistical data, we use different types of diagrams or graphs. Some of them are:

(i)  Pictograph

(ii) Bar graph

Pictograph

A pictograph represents the given data through pictures of objects. It helps to answer the questions on the data at a glance.

Example:

The following pictograph, shows the number of cakes sold at a bakery over five days.

Based on above pictograph, answer the following questions:

(i)  On which day, the maximum number of cakes were sold?

(a) Monday                    (b) Tuesday      

(c) Wednesday                (d) Friday

(e) None of these

Answer (a)

Explanation: Clearly from the pictograph, we can say that on Monday the maximum number of cakes were sold.

(ii) How many total number of cakes were sold over five days?

(a) 150                          (b) 160          

(c) 170                          (d) 180

(e) None of these

Answer (d)

Explanation: Total number of cakes sold over five days.

\[=50+30+35+20+45=180\]

Bar Graph

A bar graph is a pictorial representation of numerical data in the form of rectangles (or bars) of equal width and varying lengths. The lengths (or heights) of a rectangle depends upon the number it represents. The distance between each rectangle remains same.

Note:

• The rectangle in a bar graph can be drawn vertically or horizontally.
• In a bar graph if two sets of data are to be presented simultaneously, it is called a double bar graph, which is used in comparing the data.

Example: The bar graph given below represents the sales of books (in thousand number) from five branches of a publishing company during a year.

Sales of books (in thousand numbers) from five branches Science, English, Maths, Hindi and Computers of a publishing company daring a year.

Based on above information answer the following questions.

(i)   What is the ratio of sales of books of Hindi to the sales of books of science?

(a) \[1:11\]                     (b) \[10:11\]        

(c) \[3:5\]                       (d) \[4:7\]

(e) None of these

Answer (b)

Explanation: Clearly, from the bar graph, we get required ratio \[=40000:44000=10:11\]

(ii) What is the difference between the maximum and minimum number of books in that year?

(a) 10,000                      (b) 20,000       

(c) 30,000                      (d) 40,000

(e) None of these

Answer (b)

Explanation: Required difference \[=50000-30000=20000\]