Table B-1c. Estimated Standard Errors of Percentage for Hazardous Material Shipment Characteristics by Mode of Transportation: 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]
|Mode of transportation||Value||Tons||Ton-miles|
|Air (includes truck and air)||–||0.6||–||–||–||–|
|Parcel, U.S.P.S. or courier||0.1||–||–||–||–||–|
|Other multiple modes||0.2||0.1||0.2||0.2||0.9||S|
|Other and unknown modes||0.2||0.2||0.1||-||0.4||0.1|
– Represents and estimate equal to zero or less than 1 unit of measure.
S Estimate does not meet publication standards because of highly 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: Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, Hazmat Data, December 2004.