1. Graphing Miss Sauer’s 7th Grade Science Class

2. Graphing
AIM: How do you create a graph? How do you know whether to use a line graph, a bar graph, or a pie chart?
HOMEWORK: Complete bar graph “Give It a Try”

3. DO NOW:
1. Both of these figures display the same information but in different ways. Which figure is easier to understand? Explain.
2. If you need to get specific data, such as an exact number of students who earned a B, which figure would you use? Explain.

4. Graphing
Motivation:

5. Choosing the right graph:
Data tables provide an organized way of viewing information, and graphs are pictures of the information in a data table. Sometimes it is faster and easier to interpret data by looking at a graph. It is important to choose the type of graph that best illustrates your data.
Next we will look at the best uses for 3 of the most common graphs.

6. Types of graphs – Bar Graph
A bar graph is best used for comparing data quickly and easily, such as the grade distribution of students enrolled in a science class or the growth of plants in different pots.
Bar Graph - Comparison

7. Types of graphs – pie Graph
A pie graph is best used for showing percentages, such as the percentage of the student body who picked certain entrees for lunch or the percentage of your allowance that will go toward purchasing various things.
Pie Graph - % (% out of 100%)

8. Types of graphs – line Graph
A line graph is best used for looking at continuous data, such as the number of bathing suits sold each month during the year or the change in your sister’s height throughout the year.
Line Graph – Continuous Data

9. Types of graphs - exercise
What graph type do you think best presents this set of data? Explain.

10. Types of graphs - exercise
What graph type do you think best presents this set of data? Explain.

11. Types of graphs - exercise
What graph type do you think best presents this set of data? Explain.

12. What do I need to set up a graph?
Title Label x-axis & y-axis Label x-axis & y-axis units (write in parathentheses next to the label of the axis) Scale x-axis & y-axis Use proper graph (line, pie, bar) Neatness Use 75% of the paper Connect the dots (for a line graph) Evenly spaced (for a bar graph)

13. titles
Titles include both the independent and dependent variables. Example: “The effect of the (IV) on the (DV)” Or “The relationship between the (IV) & (DV)” Think of the title as a picture…

14. Independent & Dependent variables
**It’s key to know what the IV & DV when you are graphing!!!

15. Independent & Dependent variables
Do you remember what an independent variable is? Independent Variable is the variable that you purposely change and test. Also called the manipulated variable. Do you remember what a dependent variable is? Dependent Variable is the factor that may change as a result of the manipulated variable (depends on the experiment). Also called the responding variable.

16. Labeling the Graph
Pneumatic Device - DRY MIX Dependent Responding Y-Axis Manipulated Independent X-Axis

17. Labeling the Graph
Time will ALWAYS be the Independent Variable and go on the x-axis. It is what is being changed.

18. Labeling the Graph Look at the graph:
-There is a title, label on each axis, no units for this graph, but would have if there were units.
-Bar graphs MUST be neat (use a ruler).
-The bars are not touching (because they data is not related).
-The bars are equally spaced.
Look at the graph:
The graph should fill ~75% of the page. Scale Properly.

19. exercise
For this table (a) identify the independent and dependent variable, (b) determine the type of graph to use, and (c) provide a title.

20. exercise
For this table (a) identify the independent and dependent variable, (b) determine the type of graph to use, and (c) provide a title.

21. Scaling a graph
Scaling the graph means numbering the grid so that the data can be displayed for comparison. It is called scaling because you are actually making a scale, a set value per box / line for both the x-axis and y-axis.

22. Scaling a graph
Point of Origin: The first line of the graph. This is the beginning point of the graph

23. Scaling a graph
To scale a graph, you first should look at your data and determine the range of your data. You will need to include all your data on the graph.
You can then count the number of lines available on your graph.
Next, you divide the highest number of your data by the number of lines available. This will give you the value of each line on the axis. You may need to slightly adjust the value of each line to avoid decimal points.

24. Understanding Scaling
Line Graph Example:
On y-axis we have 40 lines going up.
Our data ranges from 11.0 – 17.3.
We are going to make our math / our lives easier & use a number that fits our data & divides easily.
17.3 doesn’t divide easily, but 20 does!!!
/ = 0.5
(data) / (# of lines) = value of each of the 40 lines
We use the same method to scale our x-axis.

25. Understanding Scaling
Bar Graph Example:
We use the same method (we used for a line graph) to scale our y-axis.
For the x-axis, we need to consider how many “things” we are comparing.
Example: 5 sports that we are comparing & we have lines.
/ = 6
(# of lines) / (data we are comparing) = # of lines we are skipping between each sport
Remember: the bars should be evenly spaced!

26. “Give it a try” – (Finish for hw)
Select the appropriate graph type.
Identify the independent and dependent variable.
Choose an appropriate scale.
Label the axes.
Give your graph a title.
Graph the data.

27. conclusion What is an independent variable?
What is a dependent variable?
What do I need for a graph?
Which graph do I use for comparison?
Which graph do I use for percentages that add up to 100%?
Which graph do I use for continuous data?

28. RELATIONSHIPS of Graphs
Direct: the x-axis & y-axis are both doing the same thing.
Indirect: the x-axis & y-axis are NOT doing the same thing.
Constant: Either the x-axis remains the same & the y-axis changes OR the y-axis stays the same & the a-axis changes.
Cyclic: Displays a pattern & is predictable.

29. RELATIONSHIPS of Graphs
Direct: the x-axis & y-axis are both doing the same thing.

30. RELATIONSHIPS of Graphs
Indirect: the x-axis & y-axis are NOT doing the same thing.

31. RELATIONSHIPS of Graphs
Constant: Either the x-axis remains the same & the y-axis changes OR the y-axis stays the same & the a-axis changes. OR

32. RELATIONSHIPS of Graphs
Cyclic: Displays a pattern & is predictable.