Objective: At the conclusion of the lesson, the students should be able to plot data points, draw and interpret best-fit lines or curves, and evaluate when it can and cannot be considered as a linear function.

Class/Start-Up Activity (5 min): The teacher will ask the class what they already know about linear functions. They will discuss real-life examples and the equations of these functions.

Lesson Content (50 min): 1. Introduction to plotting data points (15 min): The teacher will introduce the concept of plotting data points. The students will plot points on the coordinate plane for given data sets.

1. Best fit line (10 min): The teacher will discuss the concept of fitting a line of best fit to a set of data points. The students will plot points on the coordinate plane, draw a line of best fit and calculate the values of the line of best fit’s equation.

2. Best fit curve (10 min): The teacher will introduce the concept of fitting a curve of best fit to a set of data points. The students will plot points on the coordinate plane, draw a curve of best fit (parabola or cubic), and calculate the values of the equation of the best fit curve.

3. Linear functions and best-fit lines/curves (15 min): The teacher will discuss the differences between linear functions and best-fit lines/curves, and discuss when a best-fit line or curve could be considered to represent a linear function. The students will be asked to evaluate examples of best-fit lines/curves and decide if the data can be considered as a linear function.

Conclusion (5 min): The students will answer questions about the lesson content and discuss their answers in small groups.

Assessment (5 min): The students will be given a worksheet on plotting data points, drawing best fit lines/curves, and evaluating when they can and cannot be considered as linear functions. The teacher will assess the worksheets to ensure the students have understood the lesson content.