female chinook salmon icon Definitions

Average Levels - As stated in Title 34, the goal is to sustain natural production "...at levels not less than twice the average levels attained during the period of 1967-1991..." To attach numeric values to this goal, we need to estimate average levels of production. One problem is that average is not a precise statistical term. In statistics, the term average can apply to several measures of central tendency (Langley 1971). The most commonly used measure of central tendency is the arithmetic mean (Lapin 1975). Consequently, the public generally understands average to mean arithmetic mean and it is reasonable to assume that this was the intent of the authors of Title 34. Therefore, the definition of average will be the arithmetic mean.

Langley, R. 1971. Practical statistics simply explained. Dover Publications, Inc. New York, NY. 399 pp.

Lapin, L. 1975. Statistics: meaning and method. Harcourt Brace Jovanovich, Inc. New York, NY. 591 pp.

Source: Final Restoration Plan [  A-3 ]