Line of Best Fit
Line of Best Fit Basics
- A line of best fit (or trend line) is a straight or curved line which best represents the data on a scatter plot.
- This line may pass through some of the points, all of them, or none of them.
- It can be used to identify a trend or pattern in data points, and to make predictions.
Drawing a Line of Best Fit
- To draw a line of best fit, balance the number of points above the line with the number of points below it.
- Aim for roughly the same amount of space between the points and the line on either side.
- Avoid drawing a line that goes through every point. The goal is to get as close to as many points as possible.
Purpose of the Line of Best Fit
- The line of best fit gives us the general direction (or trend) that the data seem to be heading.
- It can also help us predict values for one variable given values of the other variable.
Interpreting the Line of Best Fit
- A rising line indicates a positive correlation between variables, while a falling line indicates a negative correlation.
- The steeper the line, the stronger the correlation between variables.
Limitations of the Line of Best Fit
- The line is only as reliable as the data. If there are extremely high or low values (outliers), the line may not accurately represent the relationship.
- Correlation does not imply causation. Just because a line of best fit indicates a correlation, it doesn’t prove that one variable causes the other to change.
Remember, the line of best fit is just an estimate of the trend, and actual data may not fall directly on the line.