Line of Best Fit 4.2 A

Goal Understand a scatter plot, and what makes a line a good fit to data.

Scatter plot Recall, data is often linear, but does not fall exactly on a line.

Line of Best Fit We draw a line to estimate the data called a “line of best fit”

Need 2 things! 1.The slope of the line is in the general direction of the points. 2. There are about half the points above the line, and half below the line.

Example

Both are following the direction, and both have the same number of points above and below. How would your predictions differ if you use line t versus line s?

Remember when… We found equations from a table of data? Let’s do it again!

Example Time (hours) Distance (miles) Find the slope of this data, and include units in your answer.

Remember! Slope is rate of change.

Homework Practice writing equations of lines, and drawing lines of best fit.