Table B-2. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for State of Origin: 2002
Table B-2. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for State of Origin: 2002
[Estimates are based on data from the Commodity Flow Survey. Because of rounding, estimates may not be additive]
| Mode of transportation | Ton-miles | CV of average miles per shipment  | 
 |
|---|---|---|---|
| CV | Std. error of percent | ||
| Total | 11.0 | – | 9.4 | 
| Truck | 11.3 | 3.2 | 9.2 | 
| Rail | 17.6 | 3.4 | 13.5 | 
| Shallow draft | S | S | 31.6 | 
| Great Lakes | – | – | – | 
| Deep draft | S | S | 31.1 | 
| Air | 30.8 | – | 4.3 | 
| Parcel, USPS or courier | – | – | – | 
| Pipeline | S | S | S | 
| Other and unknown modes | 31.3 | 0.3 | 19.5 | 
KEY: 
    – Represents data cell
  equal to zero or less than 1 unit of measure.
  
    S Estimate does not meet publication standards because of high sampling
  variability or poor response quality. 
    CV Coefficient of variation of number
NOTE: The Introduction and appendixes give information onf 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: Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, Individual State Data, December 2004.