NCERT Solutions Class 6th Maths Chapter – 9 Data Handling Examples

Example 1. A teacher wants to know the choice of food of each student as part of the mid-day meal programme. The teacher assigns the task of collecting this information to Maria.

Solution –

Maria does so using a paper and a pencil. After arranging the choices in a column, she puts against a choice of food one (|) mark for every student making that choice.

Umesh, after seeing the table suggested a better method to count the students. He asked Maria to organise the marks (|) in a group of ten as shown below-

Rajan made it simpler by asking her to make groups of five instead of ten, as shown below-

Teacher suggested that the fifth mark in a group of five marks should be used as a cross, as shown by ‘||||’. These are tally marks. Thus, |||| || shows the count to be five plus two (i.e. seven) and |||| |||| shows five plus five (i.e. ten).

With this, the table looks like-

Example 2. Ekta is asked to collect data for size of shoes of students in her Class VI. Her finding are recorded in the manner shown below-

Solution –

Javed wanted to know (i) the size of shoes worn by the maximum number of students. (ii) the size of shoes worn by the minimum number of students. Can you find this information?

Ekta prepared a table using tally marks.

Now the questions asked earlier could be answered easily. You may also do some such activity in your class using tally marks.

Example 3 – The following pictograph shows the number of absentees in a class of 30 students during the previous week-

(a) On which day were the maximum number of students absent?
(b) Which day had full attendance?
(c) What was the total number of absentees in that week?

Solution –

(a) Maximum absentees were on saturday. (There are 8 pictures in the row for saturday; on all other days, the number of pictures are less).

(b) Against thursday, there is no picture, i.e. no one is absent. Thus, on that day the class had full attendance.

(c) There are 20 pictures in all. So, the total number of absentees in that week was 20.

(a) Find the number of people preferring blue colour.
(b) How many people liked red colour?

Solution –

(a) Blue colour is preferred by 50 people.
[People = 10, so 5 pictures indicate 5 × 10 people].

(b) Deciding the number of people liking red colour needs more care.
For 5 complete pictures, we get 5 × 10 = 50 people.
For the last incomplete picture, we may roughly take it as 5.
So, number of people preferring red colour is nearly 55.

Example 5. A survey was carried out on 30 students of class VI in a school. Data about the different modes of transport used by them to travel to school was displayed as pictograph.

What can you conclude from the pictograph?

Solution –

From the pictograph we find that-

(a) The number of students coming by private car is 4.

(b) Maximum number of students use the school bus. This is the most popular way.

(c) Cycle is used by only three students.

(d) The number of students using the other modes can be similarly found.

Example 6 – Following is the pictograph of the number of wrist watches manufactured by a factory in a particular week.

(a) On which day were the least number of wrist watches manufactured?
(b) On which day were the maximum number of wrist watches manufactured?
(c) Find out the approximate number of wrist watches manufactured in the particular week?

Solution –

On completing the table-

(a) Least number of wrist watches were manufactured on Saturday (550).
(b) Maximum number of wrist watches were manufactured on Thursday (800).
(c) Number of wrist watches manufactured in whole week
= 600 + 750 + 650 + 800 + 600 + 550
= 3950.