Questions: A scatter plot is shown below. A line of best fit passes through point A and another point in the data set.
Use the drop-down menus to describe through which additional point the line of best fit passes and use that line to determine the approximate value for y when x=9.
Transcript text: A scatter plot is shown below. A line of best fit passes through point $A$ and another point in the data set.
Use the drop-down menus to describe through which additional point the line of best fit passes and use that line to determine the approximate value for $y$ when $x=9$.
Solution
Solution Steps
Step 1: Identify Point A
Point A is located at (2, 3).
Step 2: Find another point for the line of best fit
A line of best fit should pass through the middle of the data points, minimizing the distance to the points on either side. Visually, a line through A and B (10, 8.5) seems like a good fit. Another possible point could be C (6,5), but this line does not fit as well since more points will be farther away.
Step 3: Calculate the slope
Using points A (2, 3) and B (10, 8.5), the slope is (8.5 - 3) / (10 - 2) = 5.5 / 8 = 0.6875.
Step 4: Find the equation of the line
Using point-slope form with point A (2,3): y - 3 = 0.6875(x - 2). Simplifying to slope-intercept form gives y = 0.6875x + 1.625
Step 5: Approximate y when x = 9
Substitute x = 9 into the equation: y = 0.6875 * 9 + 1.625 = 6.1875 + 1.625 = 7.8125. Since the graph uses whole numbers, round to approximately 8.
Final Answer
The line of best fit passes through point B. When x = 9, y is approximately 8.