Page 116 - Ganit Kaushal

Step 2: We must choose a scale which means we must decide
how many students will be represented by a unit length of a
bar so that it fits nicely on our paper.

Here we take 1 unit length = 2 friends.

Step 3: We have labelled the horizontal axis as ‘sweets’
because we have written the names of sweets along the
horizontal axis, and we have labelled the vertical axis as
‘Number of friends’. The height of the bars will tell us which
sweet is preferred by how many friends.
Step 4: Bars of uniform width are drawn vertically upwards
for each category with equal distances between them. The
height of the bar represents the frequency of the category of sweets. Example, for Jalebi we draw a bar of
height 6 units, which is the frequency of the sweet jalebi. Similarly, we do this for the other sweets. We have
to draw bars as high as their frequencies.

Step 5: We have titled the bar graph as ‘Sweet Preferences of Friends’. It clearly explains that the data is
about the sweet preferences of a few friends. Note that giving a title to the bar graph is not mandatory; it
is optional.

Solved Examples

Ex 1. Let us look at an example of vehicular traffic at a busy road crossing in Delhi, which was studied
by the traffic police on a particular day. The number of vehicles passing through the crossing each
hour from 6 am to 12:00 noon is shown in the bar graph. One unit of length stands for 100 vehicles.
(NCERT)

Based on the above bar graph, answer the following questions:

(a) How many cars in total passed through the crossing between 6 am and noon?
(b) Why do you think so little traffic occurred during the hour of 6-7 am, as compared to the other
hours from 7 am to noon?
(c) Why do you think the traffic was the heaviest between 7 am and 8 am?

(d) Why do you think the traffic was less and less each hour after 8 am all the way until noon?

114 Mathematics-6