Ex.3.1 Q2 Data Handling  NCERT Maths Class 7
Organize the following marks in a class assessment, in a tabular form.
\(4, 6, 7, 5, 3, 5, 4, 5, 2, 6, 2, 5, 1, 9, 6, 5, 8, 4, 6, 7\)
(i) Which number is the highest?
(ii) Which number is the lowest?
(iii) What is the range of the data?
(iv) What is the arithmetic mean?
{%answer%}
What is known?
Marks in class assessment.
What is unknown?
Highest marks,lowest marks,range,arithmetic mean.
Reasoning:
Range \(= \) Highest marks\(\) lowest marks
Steps:
S\(I\) NO 
Marks 
Tally marks 
No. of students (Frequency) 
\(1\) 
\(1\) 
I 
\(1\) 
\(2\) 
\(2\) 
II 
\(2\) 
\(3\) 
\(3\) 
I 
\(1\) 
\(4\) 
\(4\) 
III 
\(3\) 
\(5\) 
\(5\) 

\(5\) 
\(6\) 
\(6\) 
IIII 
\(4\) 
\(7\) 
\(7\) 
II 
\(2\) 
\(8\) 
\(8\) 
I 
\(1\) 
\(9\) 
\(9\) 
I 
\(1\) 
The highest number is \(9.\)
The lowest number is \(1.\)
The range of the data = Highest number – Lowest number no.
\(= 9 – 1 = 8\)
\[\therefore {\text{Mean of first five whole numbers}} = \frac{{{\text{Sum of all numbers}}}}{{{\text{Total numbers}}}}\]
\[\begin{align}{\text{Arithmetic mean}} &= \frac{{4 + 6 + 7 + 5 + 3 + 5 + 4 + 5 + 2 + 6 + 2 + 5 + 1 + 9 + 6 + 5 + 8 + 4 + 6 + 7}}{{20}}\\ &= \frac{{100}}{{20}}\\ &= 5\end{align}\]