Table B-2c. Estimated Standard Error of Percentage for Export Shipment Characteristics by Domestic Mode: Percent of Total for 2002 and 1997
[Estimates are shown as percents and are based on data from the 2002 and 1997 Commodity Flow Surveys]
|Domestic mode of transportation||Value||Tons||Ton-miles|
|Std. error of percent 2002||Std. error of percent 1997||Std. error of percent 2002||Std. error of percent 1997||Std. error of percent 2002||Std. error of percent 1997|
|Air (including truck and air)||1.0||2.4||–||–||0.3||0.2|
|Parcel, U.S.P.S. or courier||0.8||0.9||–||–||–||–|
|Truck and rail||0.3||0.3||0.6||0.2||0.7||0.7|
|All other multiple modes||–||–||0.3||0.3||1.3||1.5|
|Other and unknown modes||0.4||0.8||0.3||3.3||0.2||1.8|
– Represents an estimate 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.
NOTE: 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: Research and Innovative Technologies Administration, Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, Export Data, March 2005.