NCERT Class 9 Maths Lab ACTIVITY 10
– To draw histogram of heights of students of your class.
Objective
To draw a histogram representing the heights of students using the provided data.
Materials Required
Graph paper
Geometry box
Adhesive
Sketch pens
Scissors
A piece of cardboard
Prerequisite Knowledge
Knowledge about collection of data.
Concept of histogram.
Step-by-Step Procedure
1. Organize the Data
The given heights are:
157, 159, 170, 144, 156, 163, 164, 154, 163, 164, 158, 152, 165, 157, 171, 164, 172, 162, 150, 170, 151, 157, 170, 159, 163, 201, 168, 171, 160, 191, 164, 170, 182, 154, 167, 165, 171, 168, 188, 176, 160, 184, 184, 177, 165, 166.
2. Determine Class Intervals
Group the heights into equal-sized class intervals (e.g., 140–150, 150–160, 160–170, etc.) and count the number of heights in each interval (frequency).
Class Intervals and Frequency Table:
3. Draw Axes and Scale
X-Axis: Represent the height intervals (class intervals).
Y-Axis: Represent the frequency (number of students).
Use a consistent scale for both axes.
4. Draw the Histogram
Draw rectangles (bars) for each class interval.
The height of each rectangle corresponds to its frequency.
Ensure there is no gap between rectangles.
Observations
Graphical Representation
For the classes of equal widths,
The intervals are
a-b = ……….. 140–150: Bar height = 2
b-c = …………150–160: Bar height = 13
c-d = ………….. 160–170: Bar height = 16
d-e = ……….170–180: Bar height = 9
e-f = ………..180–190: Bar height = 5
g-h = ………..190–200: Bar height = 1
i-j = ………..200–210: Bar height = 1
Frequencies are
f1 = ………… 2
f2 = ………..13
f3 = …………. 17
f4 = ………….9
f5 = …………..5
f6 = …………..1
f7 = …………..1
Result
We have drawn a histogram of equal widths and varying widths by using the collected data of the heights of students.
Application
Histograms can be used pictorially in representing large data in a concise form.
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