Graphing Types of graphs & how to create graphs in Excel

Types of Graphs  Linear – 1. Shape = straight line 2. Trendline in Excel = linear 3. Equation : y = mx + b m = slope ; b = y-intercept (if X gets larger, Y gets larger)

Types of Graphs (cont.)  Types of Linear Graphs: 1. Linear Relationship: Has a Y-intercept (b); doesn’t start at (0,0) 2.Direct Relationship : No Y-intercept (b); starts at (0,0) equation becomes y = mx

Linear Relationship Graph Acceleration (m/s 2 ) Net Force (N)

Direct Relationship Graph

Types of Graphs (cont.)  Quadratic – 1. Shape = parabola 2. Trendline in Excel = polynomial 3. Equation : y = ax 2 (if X gets larger, then Y gets larger by the square of X)

Quadratic Relationship Graph

Types of Graphs (cont.)  Inverse – 1. Shape = hyperbola 2. Trendline in Excel = power 3. Equation: y = a/x (Excel: y = ax -1 ) (as X gets larger, Y gets smaller)

Inverse Relationship Graph

Creating a Graph in Excel 1. 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

Creating a Graph in Excel (cont.) 2. Create Excel data table 3. Highlight data to graph (values only) 4. Insert  Scatter  Scatter with only markers (upper left choice) 5. Under Chart Tools tab  Layout Chart Title Axis Titles (label & unit)

Creating a Graph in Excel (cont.) Layout (cont.) Add Trendline Add Legend – when necessary Set intercept (0,0) – when necessary