In this activity, you will generate a two-dimensional line graph which represents the amount of cooling energy (measured in degree-days) used by the Veterans Hospital in Salem, Virginia from October 1995, through December 1996. The degree-days show how much energy was used to cool the building for a number of months. In this activity, you will be plotting the amount of energy used each month (degree-days), verses the months. The independent variable (months) is plotted on the x axis, and the dependent variable (degree-days) on the y axis. That is, the degree-days used by the hospital are dependent of the month.

The data for this activity was obtained from the Greenwood Partnership in Lynchburg, Virginia. The Greenwood Partnership is an architectural and engineering firm which designs and remodels buildings. The firm collected the data from the Veterans Hospital, in Salem, Virginia, before upgrading the cooling system of the hospital. It was important to know how much heating and cooling energy the hospital consumed prior to the upgrade, because the engineers used the information to make revisions. An engineer needs to know as much about the project as possible to make the safest and most cost-efficient changes.

Using Excel or the TI-83 , create a two-dimensional line graph of the amount of cooling energy used every month by the Salem Veterans Hospital. This data exists in three files; one is in Excel Data format, one is in Text format, and one is in TI-83 Group format.  If you want to use the TI-83 for this activity, then you must import the data from the computer after you download the text file.

In what month was the most cooling energy used? In what months was the least cooling energy used? Are there any trends that are present in the graph? What possible explanations are there for these trends?

A two-dimensional line graph provides a visual representation of a data set and reveals trends. Engineers can gain a basic understanding of a data set by studying simple graphs. For a more in depth analysis, an engineer could use a three-dimensional line graph. After completing this activity, go on to the 3-D Energy Consumption Activity, which is a follow up activity to this one.

Original work on this document was done by Central Virginia Governor's School students Derek Chernault and Chris Banton (Class of '99).

Copyright © 1998 Central Virginia Governor's School for Science and Technology Lynchburg, VA