The survey program plan must include all the following:
Where:
n = Minimum number of samples in a year-long survey series. However, n must be greater than or equal to 2,000 for the number of diesel samples or 5,000 for the number of gasoline samples.
Z[ALPHA] = Upper percentile point from the normal distribution to achieve a one-tailed 95% confidence level (5% [ALPHA]-level). For purposes of this survey program, Z[ALPHA] equals 1.645.
Z[BETA] = Upper percentile point to achieve 95% power. For purposes of this survey program, Z[BETA] equals 1.645.
[PHI]1 = The maximum proportion of non-compliant outlets for a region to be deemed compliant. This parameter needs to be 5% or greater (i.e., 5% or more of the outlets, within a stratum such that the region is considered non-compliant).
[PHI]0 = The underlying proportion of non-compliant outlets in a sample. For the first survey program plan, [PHI]0 will be 2.3%. For subsequent survey program plans, [PHI]0 will be the average of the proportion of outlets found to be non-compliant over the previous 4 surveys.
Fa = Adjustment factor for the number of extra samples required to compensate for samples that could not be included in the survey (e.g., due to technical or logistical considerations), based on the number of additional samples required during the previous 4 surveys. Fa must be greater than or equal to 1.1.
Fb = Adjustment factor for the number of samples required to resample each retail outlet with test results reported to EPA under § 1090.1410(e) , based on the rate of resampling required during the previous 4 surveys. Fb must be greater than or equal to 1.1.
Sun = Number of surveys per year. For purposes of this survey program, Sun equals 4.
Stn = Number of sampling strata. For purposes of this survey program, Stn equals 3.
40 C.F.R. §1090.1415