I have data that I can use to indicate what percentage of the US population falls with different groups. IE

under 100 lbs .2%

100-110 lbs. 4%

The whole will equal 100%. But I want to calculate the standard deviation of the data, but have no idea where to start. Any help would be greatly appreciated. Here is the data I am working with:

http://www.census.gov/compendia/stat...es/12s0210.pdf