Class 7 Maths Chapter 3 is the Data Handling chapter that contains information about data, data handling, and how to deal with data. It explains the different ways to organise and represent data in different formats. Class 7 Maths Data Handling is an important chapter in CBSE as the knowledge gained in this chapter will form the base for the advanced topics. You can use the MSVgo app and watch the learning videos to understand these concepts. These videos help you study anywhere, anytime and improve your performance.
As you know, videos make interactive learning and help you understand concepts easily. Watch and learn using these videos by registering on the MSVgo app. Get access to the Data Handling Class 7 NCERT solutions and prepare for the exams by quick revisions.
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.
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 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:
Month |
Average Temperature |
Jan |
11 |
Feb |
13 |
Mar |
20 |
Apr |
24 |
May |
30 |
June |
35 |
July |
38 |
Aug |
30 |
Sep |
28 |
Oct |
23 |
Nov |
16 |
Dec |
12 |
Solution: As Mode represents the value occurring more frequently, the data given in the above table shows the temperature 30 occurs for two months, i.e., May and August, in our data. Other temperature values are unique for the remaining months. Hence Mode for this data is 30.
3. Median
The Median is the middle value in the observations that divides the data into two parts. In order to find the median, we need to range the data in increasing or decreasing order and find the central value.
(i) if the number of observation is odd
Median = N + 1 / 2
(ii) if the number of observation is even
Median = (N/2 + (N/2 + 1))/ 2
Example: When the number of observations is odd
2, 4, 5, 8, 9
Median = 5
When the number of observations is even
1, 2, 3, 4, 5, 6, 7, 8
Median = 4 + 5 / 2 = 4.5
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.
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.
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.
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.
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:
Picnic Spot |
Number of Students |
Golden Temple |
11 |
Science City |
9 |
Bombay Picnic Spot |
12 |
Sun City |
8 |
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.
Year |
2017 |
2018 |
2019 |
2020 |
2021 |
Science |
27 |
35 |
29 |
37 |
39 |
Mathematics |
39 |
31 |
25 |
28 |
33 |
The steps to create a double bar graph are similar to those we discussed for the bar graph. Follow the below steps to create a double bar graph:
Step1: Draw two perpendicular lines representing the X-axis and Y-axis.
Step2: On the X-axis, write Year and mark the year values with equal spacing between.
Step3: On the Y-axis, write the number of books and draw a scale. Here we are using the scale values as 5, 10, 15, and so on.
Step4: Draw the bars for Science and Mathematics as per the number of books bought from the data in the table above.
Below graph represents the double bar graph for the number of books:
Using the above bar graph, we can compare the number of Science and Mathematics books bought by students from 2017 to 2021. The blue-coloured bars represent the number of students who bought science books, and the red bar represents the number of students who bought Mathematics books. Considering the graph, we can conclude that the number of students buying science books was more in the last four years than the students buying mathematics books.
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.
Such learning videos are available on MSVgo - download the app now and speed up problem-solving skills. The app also provides the Data Handling Class 7 Solutions for all the chapters and subjects.