Final answer:
A linear trend in sales over time can be concluded if the given monthly sales data is graphed resulting in a straight line.
Step-by-step explanation:
Based on the given monthly sales data, if the data is graphed resulting in a straight line, it indicates a linear trend in sales over time. A linear trend means that there is a direct relationship between the variables being measured, in this case, sales and time.
In the field of economics, line graphs are widely used to present continuous data about prices, wages, quantities bought and sold, and the size of the economy. The fact that the graphed data in this case shows a straight line further supports the presence of a linear trend.
For example, if the sales of a product increase by a constant amount every month, the graph of those sales over time will be a straight line, indicating a linear trend.