FDSCI 201



Guided Lab —Graphs

Name _____________________________________ Time spent ______________

Purpose: Learn to make and interpret graphs.

You are to learn which graphs to use under what circumstances and how to interpret what the graph shows. The guidelines here are universal, not just something for this class. You really do need to use a specific kind of graph for specific kinds of data/information.

The 3D-perspective column/bar graph is simply eye-candy. On a computer, where one can interactively rotate and manipulated the graph, it has some very narrow uses. Other than that it is not useful.

Do the following:

1. Using Excel, create a Column Graph/Chart using the following data.

|Month |Precipitation (inches) |

|January |23 |

|February |25 |

|March |28 |

|April |23 |

|May |13 |

|June |8 |

|July |5 |

|August |4 |

|September |15 |

|October |23 |

|November |28 |

|December |22 |

The bar/column graph is when you are comparing a single quantity for various groups or categories. In the graph you are making here you are comparing the amount of precipitation that occurs in each calendar month with the amount of precipitation in the other calendar months. Another example would be to compare the average GPA of university students versus their year in school (Freshman, Sophomore, Junior, Senior, Other).

By looking at the graph you have made here, you should be able to clearly see that the summer months have much lower precipitation than the winter months. The late spring and the early fall provide rapid transitions between the high and low levels.

2. Using Excel, create two Pie Charts using the following data (free hand on non-grid paper is not acceptable). In one Pie Chart plot the number of fires for each cause category. In the other Pie Chart plot the acres burned by each cause category.

|Cause |Number of Fires |Percentage |Acres Burned |Percentage |

|Lightning |7164 |9.9% |2119275 |61.9% |

|Recreation Related Human |30800 |42.8% |698125 |20.4% |

|Activities | | | | |

|Commercial Related Human |34057 |47.3% |605324 |17.7% |

|Activities | | | | |

A pie chart is when you want to compare the proportions of something that fall into subcategories. In the graph you are making here you are comparing the proportion of Wildfires caused by lightning, unattended campfires, cigarettes, commercial activities, other, and unknown cause. Another example where one might apply a pie chart would be to depict the fraction of the US population is various ethnic groups.

By looking at the first pie chart you can see that this data would indicate that by-far-and-away the most fires are caused by humans. By looking at the second pie chart you can see that lightning caused fires burn many more acres than human caused fires do. Comparing these two pie charts raises the question of why there are so many more human caused fires, yet those fires burn many fewer acres. You can learn more about fires in your book, but here is the short answer. First, not all lightning caused fires burn enough to even get counted. Second, many naturally occurring fires are allowed to burn as a natural part of forest health. Third, human caused fires tend to occur closer to where more firefighting resources can be brought quickly to bear. Fourth, fires closer to human development tend to be fought more aggressively. Finally, fires resulting from commercial activity are often controlled very quickly due to regulations requiring firefighting equipment be on site.

3. 2. Using Excel, create an X-Y Graph/Chart, with magnitude on the X-axis and deaths on the Y-axis, using the following data (free hand on non-grid paper is not acceptable).

|Ten Largest Earthquakes since 1900 |

|Earthquake Name and date |Earthquake Magnitude |Number of People Killed |

|Valdivia, Chile, May 22, 1960 |9.5 |1886 |

|Prince William Sound, Alaska, March 27, 1964 |9.2 |128 |

|Sumatra, Indonesia, December 26, 2004 |9.1 |227,898 |

|Kamchatka, Russia, November 4, 1952 |9.0 |0 |

|Tohoku, Japan, March 11, 2011 |9.0 |20350 |

|Ecuador-Colombia, January 31, 1906 |8.8 |1500 |

|Maule/Bio-Bio, Chile February 27, 2010 |8.8 |523 |

|Rat Islands, Alaska, February 4, 1965 |8.7 |0 |

|Medog Assam, India, August 15, 1950 |8.6 |1526 |

|Andreanof Islands, Alaska, March 9 ,1957 |8.6 |0 |

Whenever you are graphing two quantities against each other then you should be using an X-Y Scatter Plot/Graph/Chart. In the problem here you are plotting deaths versus earthquake magnitude. Another example would be to plot height versus age.

What you will notice from this graph is that there isn’t a relationship between magnitude and deaths. This is because the number of people living near an earthquake is much more important to the number of deaths than is the size of the earthquake. Also more important than the earthquake size is the type of construction used by the people that live near it. If you were to plot height versus age, then you would see a clear trend of people being taller as they get older from age 0 to about age 15. (Hopefully that is obvious to you, which is the reason that you haven’t been asked to make such a graph.) Then you would see the trend flattening out and there not being any influence of age on height. Perhaps as you reached ages >70 you would see a slight decline in height.

4. After you have completed the three problems above, cut and paste the graphs/charts that you made into a Word Document. Show them to Mr. Phillips to get credit, if you are finishing it at home print it and turn it in to the box in class.

Helpful Tips:





To make an X-Y scatter plot do the following:

1) Create two (or more) side by side columns of data with the values you want on the X-axis (horizontal axis) in the first (left-hand) column and the values that will be on the Y-axis (axes) in the columns to the right of the first. Select this data.

2) Click on the Chart Wizard button or choose Insert/Chart from the menu bar (or whatever is the equivalent process in the program you are using).

3) In the Chart Wizard choose the X-Y (scatter) graph/chart type

4) Make sure that the source data has correctly assigned you data to the X and Y values. It should have done it correctly automatically if you did step 1.

5) Label the graph and axes with the correct information and click finish.

[pic]

Your graph should resemble the graph above. Obviously, your graph will be different because your data will likely be different.

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