Theoretical statistical errors on a number basis

The ultimate that can be obtained by representative sampling may be called the ideal sample. A powder may be considered as made up of two components A and B. The probability that the number fraction p) of the bulk in terms of A shall be represented by the corresponding composition ip) of an ideal sample can be computed from the number of particles of/1 and B in the sample ( ) and the bulk N). 

For a normal distribution of variance, the spread of data about the mean is described by the probability equation 

Upper limit Lower limit Median value (jc)  

Consider a bulk made up of 8000 white balls and 4000 black balls from which 750 are extracted. Substituting in equation (1.4)  

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