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FIGURE 4-8 Joint distribution of intakes and requirements from a hypothetical population of 3,000 individuals. Intakes are independent of requirements. The mean intake is 1,600 units and the median requirement (Estimated Average Requirement [EAR]) is 1,200 units. The triangle labeled A is bounded by the intake = EAR line and the 45° line where intake = requirement. Points above the 45° line (shaded area), represent those individuals whose intakes are above the EAR, but below their own individual requirement. Individuals in triangle B have intakes below the EAR, yet above their own requirement. The number of people in triangle A is approximately equal to the number in triangle B.

on both their usual intake and their requirement and such information is rarely available. A similar number of individuals are represented by points in triangle A and in triangle B, and therefore the number above the 45° line (where intake = requirement) can be approximated by counting the number to the left of the intake = EAR line. Essentially, the EAR cut-point method substitutes the individuals in B for the individuals in A. It is easier to count the number of individuals to the left of the intake = EAR line than those above the 45° line because this only requires information on each individual's intake. Therefore, to use this method, the only information required is each individual's usual intake of the nutrient and the EAR of the group; individual requirements are not needed.

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