
 Westgard Quality Corporation © 1999, ZStats 5: Sum of Squares, Variance, and the Standard Error of the Mean 
  The calculation of a mean is linked to the central location or correctness of a laboratory test or method (accuracy, inaccuracy, bias, systematic error, trueness) and the calculation of an SD is often related to the dispersion or distribution of results (precision, imprecision, random error, uncertainty). 
  Calculation of the mean of the means of samples (the standard error of the mean) 
  The mean of the sampling distribution is always the same as the mean of the population from which the samples were drawn. 
 www.westgard.com /lesson35.htm (2112 words) 
