For example, to achieve probable error within 10% for a beef manure stockpile, one would need 17 sub-samples to characterize total N, 20 sub-samples for P, 32 for K, 121 for [NH.sub.4-]N, and 692 sub-samples for [NO.sub.3-]N
For solid manures, it seems possible to estimate the total N, P, and K in a stockpile within 10% probable error with a moderately intensive sampling plan (collecting 21 - 27 sub-samples and combining them to form one composite sample).
The t is Student's t value for a specified probability; CV is the coefficient of variation; and p is a percent probable error. Table 2a Comparison of selected chemical characteristics of solid animal manures from Colorado and Midwest (dry weight basis).
where: Ep is the probable error, and S[G.sub.25] and S[G.sub.75] are the specific gravities corresponding to the 25% and 75% ordinates respectively.
Specific gravity of separation = 1.48; Feed medium specific gravity = 1.32; Probable error 0.0175.
Like any good synthesis, however, this study makes the material new again by rewriting it, emphasizing updates, making corrections, pointing to probable errors
, drawing out descriptions for purposes of clarification, and adding the author's own discoveries, assumptions, and opinions.
Practically it is necessary to determine not marginal, but most probable errors
Moreover, the Boston Fed's study data include a substantial number of obvious and probable errors
. For example, there are no fewer than 22 cases implying loans with large negative interest rates.
This is larger by a factor of 1.0034 than the value of 1.0006, which was calculated from observations of pressure, temperature and humidity. Probable errors
in the length measurements were too small to account for this discrepancy.