Data consists of any raw information that we collect to gain knowledge about it or compare it with another set of data. Data is collected as facts and figures to fulfil a certain task.

Examples of Data: Number of employees in an office, cricket score of all the teams in a series

Data handling refers to data collection, organisation, and representation to draw insights from it.

1. Data Collection

Data collection is the first step of data handling, and it depends upon the requirement of data. For data collection, we should know the use of data or why we are collecting it. If we need to compare the scores of toppers in Maths for all classes, then we need the data of all classes and not a single class.

 2. Data Organisation

Data Organisation is a must to understand the data. It is necessary that we systematically organise the data to get an understanding. Primarily, data gets collected into tables to make it readable and easy to understand.

3. Data Representation

In order to get insight from data, there should be a specific value representing the entire data. As an example, Average can be used for Data Representation. The Average, also called the central tendency of data, lies between the minimum and maximum value of data.

1. Arithmetic Mean

It is the average of the data values. We can calculate it by dividing the total of the observed values by the count of observation. It can be represented by an x-bar.

If x1, x2, x3, …, xn represents the observations, the arithmetic mean will be as below:

Arithmetic Mean = (x1 + x2 + x3 + … + xn) / n

Example: We have the marks of Maths for class 7 students as below:

89, 90, 76, 85, 95, 92, 83, 88, 87, 75

Average Mean = (89 + 90 + 76 + 85 + 95 + 92 + 83 + 88 + 87 + 75) / 10 = 86 is an average score.

Range

Range is the difference between the maximum and minimum observation values.

Range = Largest Value – Smallest value

Example: We have the age of students of class 7th as below:

11, 12, 12, 11, 14, 11, 13, 11, 13, 12

Range = Maximum Age - Minimum Age = 14 - 11 = 3

2. Mode

Mode refers to the observation repeating for the maximum number of times or more frequently.

Example: We have the average value of the temperature for Amritsar for one year as below:

A bar graph represents data in pictorial form using bars with uniform width. The bars can be vertical or horizontal with equal space in between. It is an effective way of data representation that is easy to interpret and compare. We can see the bar graphs in magazines and newspapers to compare data between different sets of data.

Example: A school asked the class 7 students to choose a picnic spot. Below is the number of students who voted for a specific post:

Below are the steps that you can use to create a bar graph. Here we are creating the vertical bar graphs.

Step1: Draw two perpendicular lines on X-axis and Y-axis.

Step2: On X-axis, write the picnic spots separated by uniform spacing, and on Y-axis, write the number of students.

Step3: On Y-axis, choose a measuring scale. For example, we can write the values on the Y-axis as 0, 2, 4, 6, and so on, separated by equal space.

Step4: Create bars having a height equal to the number of students. For example, the height of the first bar will be 11.

Refer to the below graph to see how it will represent the data:

The above bar graph contains the information about preferences of the picnic spots for the class 7 students. It demonstrates that the maximum number of the students have chosen Bombay Picnic Spot because the respective bar has the maximum height compared to other picnic spots.

A double Bar Graph is also the pictorial representation of the data like a bar graph, but in the double bar graph, we use two bars to compare the data of two groups.

Example: Below is the data of students who bought science and mathematics books for the year 2017 to 2021.

Chance

In our daily lives, we encounter situations that are certain to happen as well as those about which we are not very sure. For example, there will be a holiday on 15th August, which is certain, while tomorrow will be a cloudy day that has some chance of occurrence. Similarly, tossing a coin and getting ahead is not certain.

Probability

Probability is a study of chance that measures the chance of occurrence of any event. For example, when we toss a coin, there is an equal chance of getting a Head and a Tail. Use the below formula to calculate probability.

Probability = The number of favourable outcomes divided by a total number of possible outcomes.

Example: Consider we want to find the probability of getting a six on a dice.

Solution:

Probability = The number of favourable outcomes divided by a total number of possible outcomes.

Favourable Outcomes = 1 because there is a single chance of getting a six when we throw a dice

Class 7 Maths Chapter 3 Data Handling is a crucial chapter that teaches how to handle the data in the form that one can infer maximum information from it. Also, the chapter explained different ways to organise and represent data. Videos are a great way of learning that increases the knowledge grasping power.