Class 8 NCERT Solutions - Chapter 5 Data Handling - Exercise 5.1

Question 1. For which of these would you use a histogram to show the data?

(a) The number of letters for different areas in a postman’s bag.

(b) The height of competitors in an athletics meet.

(c) The number of cassettes produced by 5 companies.

(d) The number of passengers boarding trains from 7:00 a.m. to 7:00 p.m. at a station.

Give reasons for each.

Solution:  

(b) The height of competitors in an athletics meet.

(d) The number of passengers boarding trains from 7:00 a.m. to 7:00 p.m. at a station.

Reason:  

Histogram is a graphical representation of data when the data is represented using the class-interval, where class-interval is the numerical width of any class.

As the cases mentioned in the options (b) and (d) data can be divided into class-intervals, therefore histogram can be used for representing the data.

Whereas in the cases (a) and (c) the data can’t be divided into class-intervals, thus histogram can’t be used for representing the data.

Question 2. The shoppers who come to a departmental store are marked as: man (M), woman (W), boy (B), or girl (G). The following list gives the shoppers who came during the first hour in the morning:

W W W G B W W M G G M M W W W W G B M W B G G M W W M M W W

W M W B W G M W W W W G W M M W W M W G W M G W M M B G G W

Make a frequency distribution table using tally marks. Draw a bar graph to illustrate it.

Solution:  

Frequency distribution table using tally marks:

👁 Frequency distribution table

The bar graph to illustrate data:

👁 Bar graph

Question 3. The weekly wages (in ₹) of 30 workers in a factory are.

830, 835, 890, 810, 835, 836, 869, 845, 898, 890, 820, 860, 832, 833, 855, 845,

804, 808, 812, 840, 885, 835, 835, 836, 878, 840, 868, 890, 806, 840

Using tally marks make a frequency table with intervals as 800–810, 810–820 and so on.

Solution:

Frequency table with intervals as 800–810, 810–820 and so on using tally marks are given below:

👁 Image

Question 4. Draw a histogram for the frequency table made for the data in Question 3, and answer the following questions.

(i) Which group has the maximum number of workers?

(ii) How many workers earn ₹850 and more?

(iii) How many workers earn less than ₹ 850?

Solution:  

👁 Image

(i) Group 830-840 has the maximum number of workers working, i.e., 9.

Reason: When seeing the graph we can observe that group having weekly wage 830-840 there are 9 workers working.

(ii) 10 workers earn more than or equal to ₹ 850.

Reason: When seeing the graph we can observe that group having weekly wage more than or equal to ₹ 850, there are 10 workers working when we add all the workers having wage more than or equal to ₹ 850.

(iii) 20 workers earn less than ₹ 850.

Reason: When seeing the graph we can observe that group having weekly wage less than ₹ 850, there are 20 workers working when we add all the workers having wage less than ₹ 850.

Question 5. The number of hours for which students of a particular class watched television during holidays is shown through the given graph.

Answer the following:

(i) For how many hours did the maximum number of students watch TV?

(ii) How many students watched TV for less than 4 hours?

(iii) How many students spent more than 5 hours in watching TV?

👁 Image

Solution: 

(i) By observing the graph we can find that the maximum number of students i.e. 32 watched TV for 4 to 5 hours.

(ii) The students who watched TV for less than 4 hours are 34 students.

Reason: 

Students who watch TV for 1-2 hours : 4

Students who watch TV for 2-3 hours : 8

Students who watch TV for 3-4 hours : 22

Therefore, the student who watched TV for less than 4 hours are 4+8+22 = 34

(iii) The students who watched TV for more than 5 hours are 14 students.

Reason:

Students who watch TV for 6-6 hours : 8

Students who watch TV for 6-7 hours : 6

Therefore the student who watched TV for more than 5 hours are 8+6 = 14