**Data Handling**

**Question 1.****Use the bar graph to answer the following questions.**

**(a)** Which is the most popular pet?**(b)** How many students have dog as a pet?

**Solution:**

Clearly, from the given bar graph :

**(a)** The most popular pet is cat.**(b)** Eight children have dog as a pet.

**Question 2.****Read the bar graph which shows the number of books sold by a bookstore during five consecutive years and answer the following questions :(i)** About how many books were sold in 1989? 1990? 1992?

**(ii)**In which year were about 475 books sold? About 225 books sold?

**(iii)**In which years were fewer than 250 books sold?

**(iv)**Can you explain how you would estimate the number of books sold in 1989?

**Solution:**

Clearly, from the given graph, we have

**(i)**Number of books sold in the year

**1989 :**170 (approx.)

**1990 :**475 (approx.)

**1992 :**225 (approx.)

**(ii)**In the year 1990, about 475 books were sold. In the year 1992, about 225 books were sold.

**(iii)**Fewer than 250 books were sold in the years 1989 and 1992.

**(iv)**It can be estimated using the height of the bar such that height of 1 cm = 100 books.

**Question 3.**

Number of children in six different classes are given below. Represent the data on a bar graph.**(a)** How would you choose a scale?**(b)** Answer the following questions :**(i)** Which class has the maximum number of children? And the minimum?**(ii)** Find the ratio of students of class sixth to the student of class eighth.

**Solution:****(a)** Start the scale at 0. The greatest value in the data is 135, so end the scale at a value greater than 135, such as 140. Use equal divisions along the axes, such as increments of 10. Here, we take 1 unit for 10 children. The bar graph is as under :**(b) (i)** The fifth class has the maximum number of children. The minimum number of children are in class tenth.**(ii)** Ratio of students of class sixth to eighth is 120 : 100 = 6 : 5.

**Question 4.****The performance of a student in 1st Term and 2nd Term is given. Draw a double bar graph choosing appropriate scale and answer the following :**

- In which subject has the child improved his performance the most?
- In which subject is the improvement the least?
- Has the performance gone down in any subject?

**Solution:**

The graph is as under :

- In Mathematics the child has improved his performance the most.
- In Social Science the child has improved his performance the least.
- Yes, the performance has gone down in Hindi.

**Question 5.****Consider this data collected from a survey of a colony.**

**(i)**Draw a double bar graph choosing an appropriate scale. What do you infer from the bar graph?

**(ii)**Which sport is most popular?

**(iii)**Which is more preferred, watching or participating in sports?

**Solution:****(i)** The graph is as under :

It is inferred that more people prefer cricket and less athletics.**(ii)** Most popular sport is cricket.**(iii)** Watching is more preferred than participating.

**Question 6.****Take the data giving the minimum and the maximum temperature of various cities given in the beginning of this chapter. Plot a double bar graph using the data and answer the following :**

- Which city has the largest difference in the minimum and maximum temperature on the given date?
- Which is the hottest city and which is the coldest city?
- Name two cities where maximum temperature of one was less than the minimum temperature of the other.
- Name the city which has the least difference between its minimum and the maximum temperature.

**Solution:**

The graph is as under :

- The city Jammu has the largest difference in the minimum and maximum temperature on the given date.
- Jammu is the hottest city and Bangalore is the coldest city.
- The name of the two cities where maximum temperature of one was less than the minimum temperature of other are Bangalore and Jaipur or Bangalore and Ahmedabad.
- Mumbai has the least difference between its minimum and the maximum temperature.