7 Line GraphsAre used to display data to show how one variable (DEPENDENT VARIABLE) changes in response to another variable (INDEPENDENT VARIABLE).
8 Plotting a line Graph 1. Draw the axes 2. Label the axes: Horizontal axis (x-axis): Independent VariableVertical axis (y-axis): Dependent Variable2. Label the axes:Independent Variable (x ) and Dependent Variable (y)Include UNITS of Measure3. Create a scaleNeeds to cover the ranges of values from your dataSpace numbers equally along axesVariables and GraphingA good experiment attempts to control all variables except the variable(s) that are being manipulated to see if a change can be observed and a cause and effect relationship can be reasoned.Variable A property or condition that can change. A variable may or may not cause a significant change.Manipulated variable is the variable that the experimenter decides to change to see if there is or is not an effect.Responding variable is the variable that will change as a result of the change in the manipulated variable. It may also be observed and or measured to determine the quantity or quality of change.When we plot information on a graph the manipulated variable always is plotted on the X - axis and the responding variable is always plotted on the Y - axis.Independent variable is another name for manipulated variable. It is independently selected by the experimenter to be manipulated.Dependent variable is watched by the experimenter and will respond to the manipulated or independent variable if there is a relationship.These relationships can be represented on a chart or graph: Before deciding to use a chart or graph a person needs to decide if the data is continuous or categorical.Continuous is data that can be represented on a continum with infinite possibilities. Temperature for example can be represented by whole numbers, decimal numbers...Categorical is data that is represented by a limited number of examples. Temperature could be categorical if it were categorized into hot, medium, or cold. Kinds of vehicles, people's favorite food... One might argue that favorite foods could be infinite, however it can be represented by categories and a category labeled others. Therefore, limiting the possibilities.Continuous data is best shown on a line graph and categorical in bar, pie, or other kinds of charts.Extrapolation is a prediction that is made from outside (extra) the data points collected and represented on the graph.Interpolation is a prediction that is made between the data points (inter, like interstate, between or among states).
9 Plotting a line Graph 4. Plot the data 5. Draw a line of BEST FIT Using coordinate pairs (data)Data Point: the point showing the location of the coordinate pairs5. Draw a line of BEST FITA smooth line that reflects the general pattern of a graph6. Add a titleIdentify the variables or relationship shown in the graph.
10 Line of best FitEmphasizes the overall trend shown by all the data taken as a whole
11 SlopeThe slope of a graph line tells you how much y changes for every change in x.