Question

The electricity consumption data of two houses with respect to the number of persons present in the respective house is as follows: Electricity Consumed (Units) Number of Persons in a House House A House B

4	8	10
6	13	12
8	15	17
10	18	20

While plotting a double line graph with this data, what are the maximum and minimum value on the vertical scale?

• A. Maximum: 18 units
  Minimum: 8 units
• B. Maximum: 18 units
  Minimum: 10 units
• C. Maximum: 20 units
  Minimum: 8 units
• D. It is not possible to plot this data on a double line graph.

Answer 1

The correct option is C Maximum: 20 units

Minimum: 8 units
When two data sets have the same categories, they can be merged to form a double line graph.

Before merging two line graphs, we must ensure that the vertical axes have the same scale and unit.

The maximum and minimum values of the data sets may not be the same.
However, the scale on the vertical axis must have the maximum and minimum values out of both the data sets.

Hence, the maximum value on the vertical scale is the maximum electricity consumed among both houses, i.e., 20 units.
Similarly, the minimum value on the vertical scale is the minimum electricity consumed among both houses, i.e., 8 units.

The double line graph is as follows: