sum of all error contributions. The probability that the error will approach either 

 this maximum or minimum is very remote. It is much more realistic therefore to 

 establish a probable value based on each individual contribution. 



The overall probable error is related to each individual contribution by the fol- 

 lowing equation: 



AE = ^/(AEJ' + (AEJ' + ••• + (AE^)= (D 



This asumes that the individual errors and their magnitudes are subject to com- 

 plete randomness and would tend to follow a normal distribution curve. Equation 1 

 does not take into account determinate errors since it is assumed that if an error can 

 be established with regard to its magnitude and sign a proper correction can be made 

 and such an error eliminated. However, in cases where the determinate is not 

 accounted for, Equation 1 should be modified to read as follows: 



AE = AEdet ± ^^inDET (la) 



The establishment of such a relationship between the individual contributions 

 and the overall error can be found in any standard mathematical textbook and will 

 not be derived here. 



