MATH 1040 - Introduction to Statistics

Lesson 8.1 Line of Best Fit

Reading

Reading sections are from the Introductory Statistics Textbook

Lesson

Lessons 6 and 7 looked at an analysis of a single quantitative variable. This lesson explores the relationship between two quantitative variables.

We learned how to create a scatterplot in Lesson 4. Sometimes the scatterplot indicates that relationship between two variables follows a linear pattern. We can draw a line through the middle of the data. This is called a Line of Best Fit.

Any line follows the format y = mx + b with the slope m attached to the variable x and the y-intercept b added to that. We will follow the same pattern, but slightly rename the formula.

\[y = a + bx\tag{Line of Best Fit}\]

The trick is finding a and b. These will be found using a calculator, like a TI-84 or Desmos.

Technology

TI-83/84

Desmos