A trend line is a straight line that is drawn on a graph to represent the general direction of data points over time. It helps to visualize patterns, making it easier to identify whether the data is increasing, decreasing, or remaining stable. Trend lines are commonly used in various fields, including finance, economics, and science, to analyze historical data and make predictions. To create a trend line, analysts typically use statistical methods, such as linear regression, to calculate the best fit line that minimizes the distance between the line and the data points. This line can then be extended into the future to forecast potential outcomes, aiding decision-making processes in areas like stock market analysis and business planning.