Theory:

We know that histograms are created on continuous data.
 
Let us consider the data table given below and try to construct a histogram step-by-step.
 
Problem:
 
A private organization conducted a survey across hundred schools in Chennai. The organization collected the average number of kindergarten children in each classroom.
 
The data table looks like this:
 
Number of students
\(25\) - \(30\)
\(30\) - \(35\)
\(35\) - \(40\)
\(40\) - \(45\)
\(45\) - \(50\)
Frequency
\(15\)
\(35\)
\(18\)
\(25\)
\(7\)
 
Now, let us try to construct a histogram.
 
Step \(1\): Convert the data received into continuous data.
 
Here, the data is already in continuous form. Hence, no conversion is required.
 
Step \(2\): Select appropriate names and units for \(X\)-axis and \(Y\)-axis.
 
Here, the axes will look like this:
 
1276_3.png
 
Step \(3\): Now mark the class intervals along the \(X\)-axis, and the frequency along the \(Y\)-axis.
 
1276_5.png
 
Step \(4\): Now, construct rectangles with class intervals as the base, and the frequency as the height.
 
1276_4.svg