Data Handling Class 8 - NCERT Concept and Practice Questions

Data is all around us. Whether you observe it in the marks of your class test, heights of students in a class, or survey responses from your friends, each piece of information forms part of data. The chapter Data Handling in Class 8 is one of the most important in your mathematics book. It helps you collect, organise, represent, and interpret data. Most importantly it introduces you to the exciting world of probability.

In this blog we will explore each concept step by step just like your NCERT book explains it. After each section you will find practice questions so that you can test your understanding and improve your skills.

Let us begin.

What is Data

Data simply means information. It can be numbers or facts collected to answer a question or understand something. For example if you asked 10 classmates about their favourite sport and wrote down the answers, you have collected data.

When data is just listed in an unorganised way it is called raw data. For example if the marks of students in a test are written as

10 12 8 15 12 10 15 9 14

this is raw data. It tells you values, but it does not make sense until you organise it. When we organise data into a table or chart it becomes easier to read and understand.

Organising Data with Frequency and Frequency Tables

When you collect data you need to count how many times each value appears. This count is called frequency. When we list these values and their frequencies in a table we call it a frequency table.

For example if 10 occurs three times in the list above we write:

Marks Frequency
10 3
11 1
12 2

Frequency tables help us see patterns and understand the data easily.

Practice Questions

1. What is data in your own words

2. The marks of students in a class are 10 12 10 11 12 10. Prepare a frequency table

3. Why do we organise data into a table

Grouping Data Using Class Intervals

Sometimes data has many values and it is difficult to make a simple frequency table. For example if 50 students record their heights, listing each separate value becomes long. So we group continuous data into class intervals. A class interval is a range of values such as 120 to 129, 130 to 139, and so on.

In this method each group is shown with its frequency.

Class Interval Frequency
120 to 129 5
130 to 139 8
140 to 149 7

In class intervals we use several important terms:

The smallest number in an interval is called lower limit
The largest number in an interval is called upper limit
The difference between upper and lower limit is the class size
The middle value of an interval is called class mark and is found by adding lower and upper limit and dividing by 2.

Practice Questions

4. What is a class interval

5. Find the class mark of the interval 50 to 59

6. The heights of 15 students are 132 135 139 130 138 136 135 130 140 132 136 138 139 132 135. Organise these into class intervals 130 to 134, 135 to 139, 140 to 144

Give your child the opportunity to strengthen their Class 8 maths skills with hands-on data handling practice. Book a Free Trial today with PlanetSpark Mathematics.

Pictographs and Representing Data with Pictures

Pictures help us understand data visually. A pictograph uses pictures or symbols to represent a number of items. Each symbol stands for a certain number of items. For example if one icon represents 10 animals, two icons represent 20 animals and so on.

Pictographs are useful when data needs to be presented in a simple visual form.

Practice Questions

7. Draw a pictograph to show the number of fruits sold in a shop using one symbol to represent five fruits

8. Why are pictographs helpful when showing data

Bar Graphs and Double Bar Graphs

A bar graph uses bars of equal width. The height of each bar shows the frequency or how many times a value or group occurs. Bar graphs make it easy to compare different groups.

A double bar graph represents two related sets of data next to each other so we can compare them. For example you can compare boys and girls favourite sports using a double bar graph.

Practice Questions

9. Draw a bar graph for the following frequency table

Colour Frequency
Red 6
Blue 4
Green 5

10. What is the difference between a bar graph and a pictograph

Histograms for Representing Continuous Data

A histogram is similar to a bar graph but the bars touch each other. It is used when the data is continuous like ages or weights. A histogram helps us see how data is distributed over different intervals.

Because the data is continuous there are no spaces between bars. This is the main difference between a histogram and a bar graph.

Practice Questions

11. Why are histograms used instead of bar graphs for continuous data

12. If you make a histogram for marks of students what will the bars show

Circle Graphs or Pie Charts

A pie chart is a circular graph where the whole circle represents the total data. The circle is divided into parts called sectors. Each sector shows how big each category is compared to the whole.

To draw a pie chart we first find the percentage of each category. Then we convert that percentage to an angle out of 360 degrees because a full circle has 360 degrees.

For example if 40 percent of students play football then the sector for football will be 40 x 360 = 144 degrees.

Practice Questions

13. The favourite games of students are football 40 percent, cricket 30 percent, chess 15 percent, others 15 percent. Find the angle for each category to draw a pie chart

14. Draw a pie chart for the following

Fruit Number of Students
Apple 12
Mango 8
Banana 10
Grapes 10

Probability and Chance

Probability tells us how likely an event is to happen. We do probability when we cannot predict the exact outcome but know all possible outcomes.

A random experiment is something whose result we do not know before doing it. When all outcomes are equally likely, we use this formula:

Probability of an event = Number of favourable outcomes divided by total number of outcomes

For example when you roll a die the probability of getting a 3 is 1 out of 6 because there is only one favourable number and total six possible outcomes.

Practice Questions

15. What is a random experiment

16. A die is rolled once. What is the probability of getting an even number

17. If a bag contains five red and seven black balls what is the probability of drawing a black ball

18. A coin is tossed 50 times and heads come up 22 times. What are the outcomes and is this a random experiment

19. Which is more likely to occur rolling a 1 or rolling a number greater than 4 on a die

20. A bag contains four green three blue and three red balls. Find the probability of drawing a blue ball and finding the probability of drawing a red ball

Final Tips for Class 8 Students

You learn better when you practice. Always organise raw data into a table first. Use neat graphs with titles and labels. Practice drawing bar graphs circle graphs and histograms on squared paper. When calculating probability always write total and favourable outcomes clearly before dividing. With regular practice you will find data handling easy and enjoyable.

Join PlanetSpark’s Summer Communication Program for Kids

PlanetSpark helps children develop not only academic skills but also essential life skills, including analytical thinking and problem-solving through fun activities. Here’s what your child can gain:

• Improved confidence in presenting data and information

• Enhanced analytical and problem-solving skills through practical exercises

• Interactive and fun learning sessions for better understanding of concepts

• Personalised guidance from experienced educators

• Exposure to real-life examples that connect maths concepts to daily life

• Opportunity to participate in activities and competitions to test knowledge

Turn your child’s summer into a confidence-building and learning journey with PlanetSpark. Book a free trial class today and let your child explore the joy of learning through practical and fun methods.

Conclusion

Data handling is an essential part of Class 8 Mathematics. It helps students collect, organise, represent, and interpret information in a meaningful way. Learning how to create frequency tables, bar graphs, histograms, pie charts, and calculating probability not only improves your mathematical skills but also develops critical thinking. Regular practice of the concepts and solving problems strengthens understanding and builds confidence. With these skills, you can easily analyse information from surveys, experiments, and real-life situations.

Mastering Data Handling lays a strong foundation for higher classes and practical applications in daily life. Remember, the more you practise, the easier it becomes to understand patterns, trends, and chances.