If you are doing this lab manually then download the Excel worksheet filled in with sample data and replace the data with your own.
There is a much easier (and more accurate) way of doing this assignment but it requires access to a Windows 95/98 machine with a fair amount of hard drive space (~10MB). You must also have either Netscape or Explorer operating and you must have a program to decompress UNIX tar and gzip compressed file format. If you don't have a decompression program, I recommend considering Netzip which attaches to your browser and handles tar and zip files, winzip (a popular program that I have never used) or godzip (also a stand alone and my favorite... a stand alone program). None of these programs are free (although there are good and free decompression programs, none of the free ones I have been able to find handle tar files. Netzip can be downloaded and used free for 30 days and godzip can be downloaded and used free about twenty times (download evaluation copy).
Once you have the ability to decompress files, go to the USGS online data sets. There you will find manuals for the DEM datasets and a listing of all available DEM's organized by state or pick the map out using a graphical interface. Click on the dataset you want to download. If you are using Netzip, you will have to use the extract command to put the dataset where you can get at them.
The dataset you have down loaded is in SDTS format and must be converted back to DEM format to be read by most mapping software. A free conversion program (DOS unfortunately) is available from the U.S. Bureau of Land Management called sdts2dem.exe (again, it is in compressed format and must be decompressed before use). Be sure to read the brief instructions on how to use the program.
Now you're about done. You should next download a nifty little (actually it's quite big) program, microdem available free from a Peter Guth at the U.S. Naval Academy. It's a neat, powerful program but has many little glitches which cause it to freeze so it can be frustrating.
Once you have microdem installed, use it to open the DEM you converted with sdts2dem.exe. Play around with the program. You should be able to make drape, contour, perspective, etc. views of your map. Use the analysis menu and the Elevations histogram option to generate the statistics and elevation histograms you'll need for this exercise. Note that the elevation histogram switches the x and y axes and reverses the numbering order from the way I did in the lab handout. Also note that the hypsometric curve (what microdem calls the Strahler Elevation Distribution) shows cumulative elevation higher rather than cumulative elevation lower. Neither of these minor differences should cause any problem. Feel free to use the microdem format rather than mine.
Good luck.
Download free evaluation copy of Netzip
Download a free evaluation copy of Godzip
Download an evaluation copy of Winzip
Download SDTS2DEM.EXE from U.S. Bureau of Land Management (remember it's zipped)
U.S. Geological Digital Elevation Model (DEM) websites