Ideas for Teaching

Calculating Percentages

Let's Calculate!

Data is available for every county in the country in two places:

The Tornado Project (click on All Tornadoes)
NOAA National Climatic Data Center's Storm Events Database

The two datasets are nearly the same, as the former is based on the latter. The latter database is the official archive for the US.

I suggest making this interesting for your students by looking for your state and county. I'll use my own, Cleveland County, Oklahoma, for the example.

Example: Cleveland County, Oklahoma

First count was done using data from the Tornado Project's listing for Cleveland County.

**Percentages of F-Scale Ratings for Cleveland County, Oklahoma tornado reports**
Tornado Rating	Number	Percentage
Weak: F0-F1	26	59%
Strong: F2-F3	17	39%
Violent: F4-F5	1	2%

Next is from the NCDC database:

**Percentages of F-Scale Ratings for Cleveland County, Oklahoma tornado reports**
Tornado Rating	Number	Percentage
Weak: F0-F1	26	50%
Strong: F2-F3	20	38%
Violent: F4-F5	2	4%
Unknown (or unmarked)	4	8%

Conclusions

Our numbers do not match those of the full dataset that the Tornado Project had and using two different data sources gave us different numbers. Adding more counties may help the numbers stabilize. A suggestion would be to try by regions in the country, too, and compare them. Try several counties in central Oklahoma and compare the results with the counties in Massachussettes.

To expand on this a little, see page 3...

Last updated: March 26, 2002
Created by: DSZ