Title:
Calculation of the Standard Deviation of a Set From the Mean and Standard
Deviation of its Mutually Exclusive Subsets
Author(s):
Domingo J. Carreira
Publication:
Concrete International
Volume:
3
Issue:
9
Appears on pages(s):
75-78
Keywords:
compressive strength; concretes; evalua
tion; quality control; standard deviation; statistical
analysis; variations.
DOI:
Date:
9/1/1981
Abstract:
An equation is presented to find the standard deviation of a set of data in terms of the mean and the Standard deviation of its mutually exclusive arbitrary subsets. The equation is suitable for either programmable calculators or hand calculations as shown in the examples. The equation is useful for statistically evaluating concrete production in terms of statistical parameters of previously evaluated test results using normal distribution. Also, some approximations are discussed.