CBSE Class 7 Mathematics Chapter 3: Data Handling NCERT Solutions

NCERT Solutions PDF Class 7 PDF

This chapter focuses on understanding and organizing data. The NCERT Solutions for Class 7 Mathematics, Chapter 3, 'Data Handling,' provide clear explanations and step-by-step solutions for various exercises. Students will learn how to collect, organize, and represent data using tables and tally marks. Key concepts covered include finding the range, calculating the arithmetic mean, and understanding the significance of these measures in interpreting data sets. The solutions also introduce the concepts of median and mode, which are crucial for understanding data distribution. These solutions are designed to help students grasp the fundamental principles of data handling, enabling them to solve problems related to data analysis effectively and prepare for their examinations with confidence.

Quick info

BoardCBSE
ClassClass 7
SubjectMathematics
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 3

Chapter summary

Chapter 3 of the NCERT Class 7 Mathematics textbook, 'Data Handling,' introduces students to the basic concepts of collecting, organizing, and representing data. This solution set covers exercises on finding the range, calculating the arithmetic mean, and understanding the significance of these statistical measures. It also touches upon tally marks for frequency distribution and prepares students for more advanced data analysis techniques.

Learning outcomes

  • Understand the concept of data and its organization.
  • Calculate the range of a given data set.
  • Determine the highest and lowest values in a data set.
  • Calculate the arithmetic mean of a set of numbers.
  • Interpret data using measures like range and mean.
  • Organize data using tally marks and frequency tables.

Topics covered

Paper topics

  • Data Collection
  • Data Organization
  • Tally Marks
  • Frequency
  • Range of Data
  • Arithmetic Mean
  • Measures of Central Tendency
  • Data Interpretation

Important topics

  • Calculating the Range
  • Finding the Arithmetic Mean
  • Organizing Data with Tally Marks
  • Interpreting Data Sets

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Questions and Solutions

Question 1

Find the range of heights of any ten students of your class.

The table below shows the heights of 10 students:

S. No. Name of students Height (in feet)
1. Gunjan 4.2
2. Aditi 4.5
3. Nikhil 5.1
4. Akhil 5.2
5. Riya 5.3
6. Akshat 5.1
7. Abhishek 4.7
8. Mayank 4.9
9. Rahul 4.5
10. Ayush 4.5
Solution:

To find the range of heights, we need to identify the highest and lowest heights among the ten students.

From the table, the heights are: 4.2, 4.5, 5.1, 5.2, 5.3, 5.1, 4.7, 4.9, 4.5, 4.5 feet.

The highest height is 5.3 feet.

The lowest height is 4.2 feet.

The range is calculated as the difference between the highest and lowest values:

Range = Highest height – Lowest height

Range = 5.3 - 4.2 feet

Range = 1.1 feet.

Therefore, the range of the heights of the ten students is 1.1 feet.

Question 2

Organize the following marks in a class assessment, in a tabular form: 4, 6, 7, 5, 3, 5, 4, 5, 2, 6, 2, 5, 1, 9, 6, 5, 8, 4, 6, 7. Now, answer the following questions:

(i) Which number is the highest?

(ii) Which number is the lowest?

(iii) What is the range of the lowest?

(iv) Find the arithmetic mean.

Solution:

First, we organize the given marks in a tabular form using tally marks to count the frequency of each mark.

Marks Tally marks Frequency (No. of students)
1 I 1
2 II 2
3 III 3
4 III 3
5 IIIII 5
6 IIII 4
7 II 2
8 I 1
9 I 1

(i) The highest number in the data is 9.

(ii) The lowest number in the data is 1.

(iii) The range of the data is the difference between the highest and lowest numbers.

Range = Highest number – Lowest number

Range = 9 - 1

Range = 8.

(iv) To find the arithmetic mean, we sum all the marks and divide by the total number of students.

Sum of marks = 4+6+7+5+3+5+4+5+2+6+2+5+1+9+6+5+8+4+6+7

Total number of students = 20

Arithmetic mean = \frac{\text{Sum of marks}}{\text{Total number of students}}

Arithmetic mean = \frac{100}{20}

Arithmetic mean = 5.

Thus, the arithmetic mean of the marks is 5.

Question 3

Find the mean of the first five whole numbers.
Solution:

The first five whole numbers are 0, 1, 2, 3, and 4. Whole numbers start from 0.

To find the mean, we sum these numbers and divide by the count of numbers, which is 5.

Sum of the first five whole numbers = 0 + 1 + 2 + 3 + 4

Sum = 10

Mean = \frac{\text{Sum of numbers}}{\text{Total number of numbers}}

Mean = \frac{10}{5}

Mean = 2.

Therefore, the mean of the first five whole numbers is 2.

Question 4

A cricketer scores the following runs in eight innings: 58, 76, 40, 35, 46, 45, 0, 100. Find the mean score.
Solution:

The runs scored by the cricketer in eight innings are 58, 76, 40, 35, 46, 45, 0, and 100.

The number of innings is 8.

To find the mean score, we sum all the runs scored and divide by the number of innings.

Sum of scores = 58 + 76 + 40 + 35 + 46 + 45 + 0 + 100

Sum of scores = 400

Mean score = \frac{\text{Sum of scores}}{\text{Number of innings}}

Mean score = \frac{400}{8}

Mean score = 50.

Thus, the mean score of the cricketer is 50.

Question 5

The following table shows the points of each player scored in four games:
Player Game 1 Game 2 Game 3 Game 4
A 14 16 10 10
B 8 4 0 6
C 8 11 Did not play 13

Now answer the following questions:

(i) Find the mean to determine A's average number of points scored per game.

(ii) To find the mean number of points per game for C, would you divide the total points by 3 or 4? Why?

(iii) B played in all the four games. How would you find the mean?

(iv) Who is the best performer?

Solution:

(i) To find the mean points scored by Player A per game, we sum A's scores and divide by the number of games played.

Player A's scores: 14, 16, 10, 10.

Number of games played by A = 4.

Mean of player A = \frac{\text{Sum of scores by A}}{\text{No. of games played by A}}

Mean of player A = \frac{14 + 16 + 10 + 10}{4}

Mean of player A = \frac{50}{4}

Mean of player A = 12.5.

Player A's average score per game is 12.5 points.

(ii) Player C played in Game 1, Game 2, and Game 4. Player C did not play in Game 3. Therefore, Player C played only 3 games.

To find the mean number of points per game for C, we should divide the total points scored by Player C by the number of games Player C actually played, which is 3.

(iii) Player B played in all four games. To find the mean score for Player B, we sum B's scores and divide by the total number of games played, which is 4.

Player B's scores: 8, 4, 0, 6.

Number of games played by B = 4.

Mean of player B = \frac{\text{Sum of scores by B}}{\text{No. of games played by B}}

Mean of player B = \frac{8 + 4 + 0 + 6}{4}

Mean of player B = \frac{18}{4}

Mean of player B = 4.5.

(iv) To determine the best performer, we compare the mean scores of all players.

Mean of player A = 12.5 points per game.

Mean of player B = 4.5 points per game.

For Player C, the scores are 8, 11, and 13 (since 'Did not play' means 0 points for that game, but for calculating the average per game played, we exclude the game not played or consider only the games played). Player C played 3 games.

Mean of player C = \frac{\text{Sum of scores by C}}{\text{No. of games played by C}}

Mean of player C = \frac{8 + 11 + 13}{3}

Mean of player C = \frac{32}{3}

Mean of player C ≈ 10.67 points per game.

Comparing the means: Player A (12.5), Player B (4.5), Player C (10.67).

Since Player A has the highest average score per game, Player A is the best performer.

Common mistakes

  • Confusing range with the highest or lowest value.
  • Errors in summing numbers when calculating the mean.
  • Incorrectly identifying the number of observations for mean calculation, especially when some data points are missing or not applicable.
  • Misinterpreting 'whole numbers' to include 1 instead of starting from 0.

Revision tips

  • Practice calculating the range for different data sets to quickly identify the spread.
  • Ensure accuracy when summing numbers for the mean calculation; double-check your addition.
  • Pay close attention to the number of observations when calculating the mean, especially in scenarios with missing data or specific conditions.
  • Review the definition of whole numbers (starting from 0) to avoid errors in mean calculations involving them.

Practice MCQs

Q1. What is the range of the following data: 10, 15, 20, 25, 30?

Q2. What is the arithmetic mean of the first five whole numbers (0, 1, 2, 3, 4)?

Q3. A cricketer scores 58, 76, 40, 35, 46, 45, 0, 100 in 8 innings. What is the mean score?

Q4. In data handling, what does 'frequency' represent?

Q5. Player A scored 14, 16, 10, 10 in four games. What is their average score per game?

Frequently asked questions

What is the main concept covered in CBSE Class 7 Maths Chapter 3?

Chapter 3, 'Data Handling,' focuses on collecting, organizing, and interpreting data using statistical measures like range and arithmetic mean.

How are NCERT Solutions for Class 7 Maths Chapter 3 helpful for students?

These solutions provide clear, step-by-step explanations for all exercises, helping students understand concepts like range and mean, and how to apply them to solve problems.

What is the formula for calculating the range of a data set?

The range of a data set is calculated by subtracting the lowest value from the highest value: Range = Highest Value - Lowest Value.

How do you calculate the arithmetic mean?

The arithmetic mean is calculated by summing all the values in a data set and then dividing by the total number of values: Mean = (Sum of all values) / (Number of values).

What are tally marks used for in data handling?

Tally marks are used to record the frequency of each data point, helping to organize raw data into a more understandable format like a frequency table.

Why is it important to understand data handling in Class 7?

Understanding data handling is fundamental for making sense of information in everyday life and forms the basis for more advanced statistical concepts learned in higher classes.

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