Algebra 1 Examples: Drawing the Line of Best Fit Step-by-Step

📚 Quick Study Guide

• 📊 A line of best fit is a straight line drawn through a scatter plot that best represents the relationship between two variables.
• 📏 It's used to make predictions based on the data.
• 📝 The line should be as close as possible to as many data points as possible, with roughly the same number of points above and below the line.
• ➕ To draw a line of best fit: First, plot the data points on a scatter plot. Then, visually estimate the line that best fits the data. Finally, draw the line.
• ✏️ Equation of a line: $y = mx + b$, where $m$ is the slope and $b$ is the y-intercept.

✏️ Practice Quiz

1. Which of the following is the primary purpose of drawing a line of best fit on a scatter plot?
   1. To connect all the data points.
   2. To show the exact relationship between two variables.
   3. To represent the general trend in the data.
   4. To create a curve through the data.
2. What does the slope of the line of best fit represent?
   1. The average of all data points.
   2. The rate of change between the two variables.
   3. The y-intercept of the data.
   4. The total number of data points.
3. When drawing a line of best fit, what should you consider about the data points?
   1. All points must be on the line.
   2. The line should minimize the distance to all points.
   3. The line should only connect the first and last points.
   4. Only points above the line matter.
4. What is the equation of a line of best fit?
   1. $y = b$
   2. $y = mx + b$
   3. $x = my + b$
   4. $y = mx$
5. If a line of best fit has a positive slope, what does this indicate about the relationship between the variables?
   1. As one variable increases, the other decreases.
   2. There is no relationship between the variables.
   3. As one variable increases, the other also increases.
   4. The variables are inversely proportional.
6. What is the y-intercept of a line of best fit?
   1. The point where the line crosses the x-axis.
   2. The point where the line crosses the y-axis.
   3. The highest data point on the scatter plot.
   4. The lowest data point on the scatter plot.
7. Why is it important to have approximately the same number of points above and below the line of best fit?
   1. To ensure the line is perfectly horizontal.
   2. To minimize bias and accurately represent the trend.
   3. To make the line easier to draw.
   4. It is not important; the line only needs to be close to the majority of points.