1. Graphing and Analyzing Data

2. 1.Why graph data? 2.Graphing data allows us to more quickly find relationships between variables and more readily see trends. 3.Graphing data also allows us to make predictions (or interpolations).

3. 4. By calculating the slope of a graph, you can also find mathematic constants useful in calculations. Density = Mass Volume Slope = Y 2 -Y 1 X 2 -X 1

4. Why Use Graphs? Example: 5. The following data was collected to see the growth of two different tomato plants over a two week period. 6. Can you quickly see a trend or relationship between the variables is the following data?

5. Time (Days)Height (cm) Heirloom Tomato PlantRoma Tomato Plant 100 202 314 446 578 610 71312 81614 916 101618 111720 121722 131724 141726

6. It may be difficult to see a trend in tomato plant growth of the two types of tomatoes just based on the numerical data. However, once the data is put into a graph, the trends are easily identifiable and predictions about future growth can also be made.

7. 7. Describe some trends that you can easily identify from the graph: Legend

8. Graphs vs. Data

9. Three Types of Graphs 8.There are three main types of graphs that we may use: a. Line Graphs b. Bar Graphs c. Pie Graphs

10. Three Types of Graphs 9. Line graphs– Line graphs are used to show the relationships between variables when the data is continuous. (Usually include time). 10. For example: The Mauna Loa Observatory in Hawaii has been monitoring the amount of CO 2 in the atmosphere over the last 48 years. Because it is continuous data a line graph should be used.

11. Example Time (Years)

12. 11. Bar Graphs– Bar graphs are used when comparing discrete events that are not continuous. 12. For Example: How many metric tons of CO 2 emissions are produced on average per person in the following regions of the world: U.S., Europe, Africa, Middle East, and Central/South America, and Asia

14. 13. Pie Graphs—Pie graphs are used to investigate percentages of a whole group. 14. For Example: Which types of fuels are used to generate power in the U.S. by percent?

15. Example of Pie Graph that shows the types of fuel used to generate power in the United States. Because the types of fuel are showed as percentage, a Pie graph is used.

16. Which graph type would you use for the following: 1.Graph the percent of all ethnicities of students at La Serna High School. 2.Compare the amount of rainfall in Whittier for each of the last 10 years. 3.Graph the trend in API scores that La Serna High School has earned over the last ten years.

17. How to Construct a Graph Always use pencil when graphing. 15. Any graph should contain these Five parts: 1. Title 2. The independent variable 3. The dependent variable 4. The scales for each variable 5. The Legend

18. Aixxs Legend X Axis Units of Independent VariableIndependent Variable Dependent Variable Units Y Axis Title This data is Fictitious. 5 10 15 20 25 30 35 40 45

19. A Graph Contains Five Major Parts The Title: depicts what the graph is about. By reading the title, the reader should get an idea about the graph. It should be a concise statement placed above the graph.

20. Aixxs Title

21. The Independent Variable: is the variable that is set up by the experimenter. It usually includes time (dates, minutes, hours), depth (feet, meters), temperature (Celsius). This variable is placed on the X axis (horizontal axis). Make sure to include proper units of measurement.

22. Aixxs X Axis Units of Independent VariableIndependent Variable 5 10 15 20 25 30 35 40 45

23. The Dependent Variable: is the variable that is directly affected by the independent variable. It is the result of what happens due to the independent variable. This variable is placed on the Y-axis or vertical axis. Make sure to include proper units of measurement.

24. Aixxs Dependent Variable Units Y Axis 5 10 15 20 25 30 35 40 45

25. The Scales for each Variable: In constructing a graph, one needs to know where to plot the points representing the data. In order to do this, a scale must be employed to include all the data points. Make the scale intervals a value that allows the graph to fill up most of your space.

26. The scales should start with 0 and climb with equal intervals. The scale of numbers will be dictated by your data values. To determine the value of each line on an axis, divide the largest measurement by the number of lines on the axis. Then round up to the nearest whole number.

27. Y-Axis Scale: Finding equal intervals to fit the data. On the Y –Axis, there are 8 lines that need to fit the largest measurement of 74 g/L. Divide the largest Measurement (74 g/L) by the number of lines (8). Then round up to the next whole number. 74 / 8 = 9.25 So, round up to 10. Each line is has a value of 10 g/L.

28. X-Axis Scale: Finding equal Intervals to fit the data. On the X-axis, there are 8 lines that need to fit the largest measurement of 40 ⁰C. Divide the largest Measurement (40 ⁰C) by the number of lines (8). Then round up to the next whole number. 40 / 8 = 5, Since this is a whole number there is no need to round up. Each line has a value of 5 ⁰C.

29. The Legend: is a short descriptive narrative concerning the graph's data.

30. Aixxs Legend 5 10 15 20 25 30 35 40 45