Table B-15a. Estimated Measures of Reliability for Hazardous Material Shipment Characteristics for Packing Group I for the United States: 2012
(Estimates are based on data from the 2012 Commodity Flow Survey)
| Description | Value | Tons | Ton-miles (1) | |||
|---|---|---|---|---|---|---|
| Coefficient of variation of number | Standard error of percent of total | Coefficient of variation of number | Standard error of percent of total | Coefficient of variation of number | Standard error of percent of total | |
| Total | 3.1 | 0.0 | 3.7 | 0.0 | 6.2 | 0.0 |
| Packing Group I | 4.9 | 0.9 | 6.3 | 1.1 | 7.1 | 1.8 |
(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/econ/cfs>.
Packing Groups I, II, and III reflect the level of hazard associated with the material being shipped. Packing Group I is the most rigorous.
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.