1. How to create a graph and how to interpret different graph designs
Graphing
How to create a graph and how to interpret different graph designs

2. Rules for plotting data
Identify the independent and dependent variables.
Ind. Variable:
A. the value you control / change
B. always on the X-axis
Dep. Variable:
A. the result of the change to the I.V.
B. always on the Y-axis

3. Rules for plotting data (cont.)
Determine the range of the I.V. to be plotted
Decide if a (0,0) origin is a valid data point
Spread the data out as much as possible (each division on the graph paper should be the largest convenient unit)
Number and label the X-axis
Repeat steps 2 – 5 for D.V.

4. Rules for plotting data (cont.)
Plot the data points
Draw line of best fit or smooth curve DO NOT play connect the dots!!!
Give the graph a title that tells what it represents
Include any other info. that is asked (formula, equation, etc.)

5. Types of Graphs Linear Relationship – 1. Directly proportional
2. Graph : straight line
3. Equation : y = mx + b
m = slope ; b = y-intercept
4. m = rise ∆y
run ∆x

6. Types of Graphs (cont.) Linear Relationship (cont.) –
5. Y-intercept (b) = the Y value when the X value is 0.
6. When b = 0, the equation becomes y = mx

7. Linear Relationship Graph

8. Types of Graphs (cont.) Nonlinear Relationships –
A. Quadratic Relationship:
1. Graph : Parabola
2. Equation : y = ax2 + bx + c
(a, b, & c are constants)
3. if b = 0 and c = 0; then y =ax2
(if x gets larger, then y gets larger by the square of x)

9. Quadratic Relationship Graph

10. Types of Graphs (cont.) Nonlinear Relationships –
B. Inverse Relationship:
1. Graph: Hyperbola
2. Equation: y = a/x or xy = a
3. As x gets larger, y gets smaller
4. This is an indirect relationship

11. Inverse Relationship Graph