CBSE Class 8 Mathematics Introduction to Graphs Assignment Set 07

Question 1. A survey conducted by an organisation in respect of illness and death among the women, found the following figures (in %)
 

Represent the above information in the form of a bar graph.
Answer: To represent the given data on a bar graph, we take the causes of death along the horizontal axis (X-axis) and the female fatality rate (%) along the vertical axis (Y-axis).
Steps to draw the bar graph:
1. Choose a suitable scale on the Y-axis, such as 1 unit = 5% fatality rate.
2. Mark the causes on the X-axis at equal intervals with uniform bar widths.
3. Draw bars corresponding to the given percentages: Reproductive Health Conditions (31.8%), Neuropsychiatric Conditions (25.4%), Injuries (12.4%), Cardiovascular Conditions (4.3%), Respiratory Conditions (4.1%), and Other Causes (22.0%).
In simple words: A bar graph visually compares different categories using rectangular bars whose heights represent their respective numerical values.

Exam Tip: Always choose a clear and uniform scale on the Y-axis so that all data points fit neatly without crowding.

Question 2. A family with monthly income of Rs. 30,000 has planned under various heads A, B, C, D, E, F, G. Draw a bar graph for the data.
 

Answer: To represent the family's expenditure data on a bar graph:
1. Plot the expenditure heads (A, B, C, D, E, F, G) along the X-axis.
2. Plot the expenditure values in thousands along the Y-axis (scale: 1 unit = Rs. 1,000).
3. Draw vertical rectangular bars corresponding to each head: A = 5, B = 4.5, C = 4, D = 3, E = 4, F = 4.5, and G = 5.
In simple words: Each bar's height accurately corresponds to the expenditure amount under that specific category.

Exam Tip: Ensure equal spacing between consecutive bars to maintain standard graphical conventions.

Question 3. The following table gives the number of students in a school during some academic years
 

Represent the above data by a bar graph.
Answer: To represent the student enrollment data on a bar graph:
1. Take the academic years on the X-axis.
2. Take the number of students on the Y-axis with a suitable scale (e.g., 1 unit = 400 students, or 1 cm = 500 students). Let us use 1 unit = 500 students.
3. Draw bars for each year: 2006-2007 (2000), 2007-2008 (2400), 2008-2009 (2200), and 2009-2010 (1800).
In simple words: Time-series data like academic years are represented chronologically along the horizontal axis.

Exam Tip: Label both axes clearly with units (e.g., Number of Students, Academic Years) to secure full marks.

Question 4. The following table shows the daily production of cars in a factory for 6 days of the week. Draw a bar graph.
 

Answer: To construct the bar graph for car production:
1. Represent the days of the week (Mon, Tue, Wed, Thu, Fri, Sat) on the X-axis.
2. Represent the number of cars produced on the Y-axis (scale: 1 unit = 50 cars).
3. Draw vertical bars with heights corresponding to: Mon = 250, Tue = 300, Wed = 200, Thu = 250, Fri = 250, Sat = 200.
In simple words: The height of each bar represents the production quantity for that specific day of the week.

Exam Tip: Verify that the scale chosen on the Y-axis accommodates the maximum value (300 cars) comfortably.

Question 5. Draw bar graphs of the following.
 

Answer: To represent the highest temperature data in a bar graph:
1. Plot the months (March, April, May, June, July) along the X-axis.
2. Plot the highest temperatures in degrees Celsius along the Y-axis (scale: 1 unit = 5°C).
3. Draw vertical bars corresponding to each month: March = 38°, April = 40°, May = 45°, June = 46°, July = 40°.
In simple words: The temperature variations across months are clearly depicted by the height of each respective bar.

Exam Tip: Include the degree symbol (°) with temperature values on the Y-axis and specify units clearly.