10 C.F.R. § 429.40
(a) Sampling plan for selection of units for testing.
(2) For each basic model of candelabra base incandescent lamp and intermediate base incandescent lamp, a minimum sample of 21 lamps shall be randomly selected and tested. Any represented value of lamp wattage of a basic model shall be based on the sample and shall be less than or equal to the lower of:
(i) The mean of the sample, where:

Or,
(ii) The lower 97.5 percent confidence limit (LCL) of the true mean divided by 0.95, where:

(b) Certification reports.
(2) Pursuant to § 429.12(b)(13), a certification report shall include the following public product-specific information:
[76 FR 12451, Mar. 7, 2011; 76 FR 24774, May 2, 2011]