# CBSE Class 8 Maths Revision Notes Chapter 5

## CBSE Class 8 Mathematics Revision Notes Chapter 5 – Data Handling

In these Class 8 Mathematics Chapter 5 Notes, students will learn about graphs. In addition, in these Class 8 Chapter 5 Mathematics Notes, students will get to know the significant details of the chapter that are important for their final examination. Along with Chapter 5 Mathematics Class 8 Notes, Extramarks will provide students with essential questions that can be asked to prepare them quickly. Moreover, Class 8 Mathematics Notes Chapter 5 will be a student’s last-minute revision guide, providing all the necessary information. These notes are based on the CBSE Syllabus

Data Handling:

In this part of Class 8 Chapter 5 notes, students will learn about data handling.

It means the process of gathering data, presenting it, and obtaining a result.

• Raw data is available to us in an unorganised state.
• We can show grouped data by using a histogram. The class intervals are on the horizontal axis, and the bars’ heights represent the class interval’s frequency. No space is shown between the bars and class intervals.
• We must organise it systematically to make valuable judgments from any data.
• Frequency means the number of times an entry appears.
• Raw data can be collected and presented methodically by using a grouped frequency distribution.
• Statistics: A branch of mathematics that deals with the gathering, presentation, analysis, and interpretation of numerical data.
• Observation: Each raw data entry is called an observation(number).
• Range: It is the difference between a data set’s lowest and highest observation.
• Array: An arrangement of raw data in increasing or decreasing order of significance.
•  Another way to present data is by using a circle graph or a pie chart. A circle graph depicts the link between a whole and its parts.
• There are some experiments where the results have an equal chance of happening.
• A random experiment means where the outcome cannot be predicted accurately.
• Each outcome of an experiment would be equally likely to happen if they had the same chance of occurring.
• Frequency: Frequency means the number of times a specific observation shows up in a data set.
• Class Interval: It is the set of raw data that has been compacted.

(i) Continuous: The upper limit of the class interval exists with the next class’s lower limit.

(ii) Discontinuous: The upper limit of the class interval does not extend over the lower limit of the next class.

• Class Limits: Every class in a graph is described by two figures known as class limits.

(i) Upper-Class Limit: It is the upper value of a given class interval.

(ii) Lower Class Limit: It is the lower value of a given class interval.

• Class size or width means the difference between a class’s lower and upper-class limits.
• Class Mark: The mid-value of a class interval.

Class mark=   Upper limit+Lower limit2

• Data visualisation in graph form:

(i) Pictograph: A symbol-based visual data representation.

(ii) A bar graph: It is a visual depiction of data that uses bars of uniform width with heights proportionate to the values.

(iii) Double Bar Graph: A bar graph shows two data sets at the same time. It comes in pretty handy if data is compared.

(iv) Histogram: A histogram is a graphical representation of frequency distribution in the rectangle form, with class intervals as bases and heights equal to given frequencies and no gaps between the rectangles.

(v) Circle Graph or Pie Chart: It is a pictorial depiction of numerical data in the form of sectors of a circle, with each sector’s area equal to the weightage of the data it represents.

• Probability: Probability is the likelihood of anything happening being quantified.

Probability of an event=Number of outcomes that makes an eventTotal number of outcomes of the experiment

(i) Experiment: It means a procedure that can provide a set of well-defined results.

(ii) Trial: It means the performance of an experiment.

(iii) An experiment where all possible outcomes are known but a specific outcome that cannot be predicted in advance is known as a random experiment.

• (iv) Equally Likely Outcomes: Experiments with an equal chance of success.

(v) Event: An event is the result of an experiment or a set of results.
• Chances and probability have real-life applications.

## Access Class 8 Mathematics Chapter 5 Data Handling Notes

### Data Handling Notes – A Quick Overview

Students will learn to present different kinds of raw data into bar graphs and charts in this chapter. Students will learn to present data on pie charts and histograms. They will also learn terms such as:

• Statistics
• Array
• Frequency
• Class interval, etc.

Students can familiarise themselves with the above terms, which will help them to gain a proper idea of what they mean. These revision notes will be helpful for you as they come with an in-depth explanation of this chapter in simple language.

Students can also download the Data Handling Class 8 Notes PDF to learn the terms quickly before their exams. Our subject experts have made the study guides according to the NCERT guidelines to make them precise. The study guides are high-quality guides to help students gain one of the best online educations.

### Data Handling Class 8 Notes – Revision Notes

(i) Data Handling

Under this section, you will be able to revise how raw data, which is data in its unorganised form, is presented to draw a satisfactory conclusion. To organise and group data, you need to learn a few terms, such as –

• Frequency – It means the number of times a particular entry occurs.
• Array – It means arranging raw data in an increasing or decreasing order of value
• Range – This is the difference between the lowest and highest observation in a given data.

(ii) Graphic Representation of Data

You can quickly revise the various ways data can be represented pictorially by going through our Data Handling Class 8 Notes.

• Pictograph
• Bar graph
• Histogram
• Pie chart

Download our Data Handling Notes to learn how to properly employ the above to present data in an organised manner.

(iii) Probability

Please go through our notes to clarify your concepts about probability. It is defined as the chances of the occurrence of a specific event when measured quantitatively. Our revision notes will also help you understand how to calculate probability.

Under this sub-topic, terms such as experiment, trial, event, and random experiment are essential. Download our Data Handling Class 8 Notes PDF to learn about these terms in detail.

### 1. According to the Revision Notes for Chapter 5 of Class 8 Mathematics, what is a histogram?

Data that exists in an organized form is known as raw data. Raw data is grouped together to make it more meaningful. When grouping data, the number of times a particular entry repeats, known as the frequency, is calculated. A frequency distribution table represents the number of times an entry occurs. But in the case of large amounts of data to be presented, the data is formed into a group.

### 2. How can data be represented?

You can represent data in the following ways:-

Tally marks: Using tallies to mark each entry of an occurrence

Pictogram: Data is represented using pictures as symbols

Bar diagram:  A bar of uniform width and different heights is used to represent the various values.

Histogram: Use of bar diagrams but no gaps in the class intervals on the horizontal axis.

Pie charts: It is shown as a circle and divided into sectors.

Ans. The type of bar graph that represents grouped data is known as a histogram. In a histogram, the vertical axis shows the frequency of the class intervals, and the horizontal axis shows the class intervals. A class interval is the grouped data having a lower and an upper limit, which is represented on the horizontal axis of a histogram.

### 3. What do you mean by grouping data according to Revision Notes of Chapter 5 of Class 8 Mathematics?

Grouping data means dividing a large number of observations into several groups. Grouping data is very important when dealing with a large volume of data present.

### 4. What do you mean by Data handling?

Data handling means the procedure done to organise the information provided in order to perform mathematical operations on it. It means collecting the raw data and showing it in a particular form. This data can be in any form, like numbers, words, etc. There are usually two types of data, they are:

• Qualitative Data
• Quantitative Data

### 5. Can we draw a bar graph using vertical bars?

Yes, we can draw a bar graph using vertical bars as well as horizontal bars.

### 6. The depiction of data through pictures is known as _____.

Pictograph. It helps to represent the data through pictures.