Table B-4c. Estimated Standard Errors for Shipment Characteristics by Shipment Weight for the United States: Percentage of Total for 2012 and 2007
(Estimates are based on data from the 2012 and 2007 Commodity Flow Surveys)
Shipment weight |
Value — standard error |
Tons — standard error |
Ton-miles (1) — standard error |
|||
---|---|---|---|---|---|---|
2012 | 2007 | 2012 | 2007 | 2012 | 2007 | |
Total | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
Less than 50 lbs. | 0.2 | 0.3 | Z | 0.0 | Z | 0.0 |
50 to 99 lbs. | 0.1 | 0.1 | Z | 0.0 | Z | 0.0 |
100 to 499 lbs. | 0.2 | 0.2 | Z | 0.0 | Z | 0.0 |
500 to 749 lbs. | 0.1 | 0.0 | Z | 0.0 | Z | 0.0 |
750 to 999 lbs. | 0.1 | 0.1 | Z | 0.0 | Z | 0.0 |
1,000 to 9,999 lbs. | 0.3 | 0.4 | 0.2 | 0.1 | 0.2 | 0.2 |
10,000 to 49,999 lbs. | 0.3 | 0.5 | 0.6 | 0.4 | 1.1 | 0.9 |
50,000 to 99,999 lbs. | 0.3 | 0.2 | 0.5 | 0.5 | 0.2 | 0.2 |
100,000 lbs. or more | 0.4 | 0.4 | 1.0 | 0.6 | 1.4 | 1.3 |
KEY: Z = Rounds to zero.
(1) Ton-miles estimates are based on estimated distances traveled along a modeled transportation network. See “Mileage Calculations” section for additional information.
NOTES: The Introduction and appendixes give information on confidentiality protection, sampling error, nonsampling error, sample design and definitions. Links to this information on the Internet may be found at <www.census.gov/cfs>.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau, 2012 Economic Census: Transportation Commodity Flow Survey, December 2014.