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Commodity Flow SurveyCommodity Flow Survey


Shipment Sampling

SAMPLE SELECTION CALCULATOR

To assist you with selecting the sample of your shipments to report in Item F, complete the item below:

Enter the total number of outbound shipments reported in Item D, page 2, of the survey form -

total number of outbound shipments:





SAMPLING INSTRUCTIONS

  1. Find the range in column (1) of the table below that contains the number of shipments you reported in Item D.
    Expanded Table for Determining Selection Rate
    (1)
    Number of Shipments Reported in Item D
    (2)
    Selection Rate
    (3)
    Number of Shipments that Should be Reported in Item F
    1 - 40 Every shipment 1 - 40
    41 - 80 2 20 - 40
    81 - 100 3 27 - 33
    101 - 200 5 20 - 40
    201 - 400 10 20 - 40
    401 - 800 20 20 - 40
    801 - 1,600 40 20 - 40
    1,601 - 3,200 80 20 - 40
    3,201 - 6,400 160 20 - 40
    6,401 - 12,800 320 20 - 40
    12,801 - 25,600 640 20 - 40
    25,601 - 51,200 1,280 20 - 40
    51,201 - 102,400 2,560 20 - 40
    102,401 - 204,800 5,120 20 - 40
    204,801 - 409,600 10,240 20 - 40
    409,601 - 819,200 20,480 20 - 40

  2. Find the selection rate, as given in column (2) of the table, that corresponds to the range you identified in the previous step.

  3. Determine the number of shipments you should report for in Item F by dividing the number you reported in Item D by the selection rate and dropping the remainder. For example, if Item D is 349, then the corresponding range from column (1) is 201-400 and the selection rate is 10. Dividing 349 by 10 and dropping the remainder gives 34. Therefore, you should report for a sample of 34 shipments.





Source: U.S. Census Bureau, Service Sector Statistics Division,
Commodity Flow Branch