Question

By connecting the center of top edge of bars of which type of plot, a line graph is obtained?

• A. Bar graph
• B. Histogram

Answer 1

The correct option is B Histogram

Consider the following histogram of the number of flights arrival per minute at different hours of the day in an airport:

When the center of top edges of each bar of a histogram is connected, a line graph is obtained as follows:

Here, the black line connected by orange dots is the line graph.

Histogram is generated form a grouped frequency table, which is continous. Time (hours) Arrivals per minute

$0600-0700$	$4$
$0700-0800$	$2$
$0800-0900$	$4$
$0900-1000$	$3$
$1000-1100$	$5$
$1100-1200$	$1$

Hence, the obtained line graph is continuous.
But, in a bar graph, data points are at discrete data points.
$\therefore$ Connecting the top edges of bars of a bar graph will not result in a proper line graph.

However, we can generate a histogram from a bar graph and finally plot a line graph.