Table B-12. Estimated Measures of Reliability for Shipment Characteristics by Commodity Group for the United States: 2002 and 1997

Table B-12. Estimated Measures of Reliability for Shipment Characteristics by Commodity Group for the United States: 2002 and 1997

[Estimates are shown as percents and are based on data from the 2002 and 1997 Commodity Flow Surveys]

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SCTG code Commodity description Value Tons Ton-miles Average miles
per shipment
CV
2002
CV
1997
Std. error of percent CV
2002
CV
1997
Std. error of percent CV
2002
CV
1997
Std. error of percent CV
2002
CV
1997
Std. error of percent
  Total 1.3 0.9 2.0 2.0 1.6 2.8 3.7 2.3 5.3 2.9 2.6 4.4
01-05 Agriculture products and fish 3.2 2.5 4.3 4.9 3.4 6.8 10.1 5.3 14.6 11.7 11.4 18.4
06-09 Grains, alcohol, and tobacco products 3.5 2.7 4.8 4.3 2.8 5.7 5.0 2.6 6.6 11.6 13.2 23.6
10-14 Stones, non-metallic minerals, and metallic ores 6.5 5.4 8.7 7.3 3.9 8.4 9.7 5.6 13.0 9.6 6.5 10.2
15-19 Coal and petroleum products 3.3 3.4 5.8 4.4 2.7 5.6 12.3 6.9 17.3 10.7 14.1 20.3
20-24 Pharmaceutical and chemical products 4.2 2.9 7.0 9.5 4.2 13.0 7.0 7.1 11.6 3.9 3.7 5.5
25-30 Logs, wood products, and textile and leather 3.6 5.3 6.8 8.8 3.6 10.4 5.7 3.8 7.7 2.5 4.5 6.1
31-34 Base metal and machinery 3.8 1.3 4.4 6.2 6.3 9.4 5.9 3.0 7.8 4.3 4.7 6.3
35-38 Electronic, motorized vehicles,
and precision instruments
4.6 1.8 5.8 6.4 2.9 10.6 7.3 3.2 10.5 3.6 2.5 5.5
39-43 Furniture and miscellaneous manufactured products 2.4 3.4 7.4 7.1 6.2 14.0 9.0 5.4 14.3 6.4 4.3 6.9
-- Commodity Unknown 9.9 11.0 7.0 22.3 18.1 20.0 41.7 15.5 47.5 8.8 9.7 13.1

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.

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: Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, United States Data, December 2004.