Comparison of Several Algorithms for Computation
of Means, Standard Deviations and Correlation 
Coefficients

Several algorithms for computation of basic
statistics are compared by their performance on 
systematically generated test data.  The statistics
calculated were the mean, standard deviation and 
correlation coefficient.  For each statistic, the algorithm
included the usual computing formulas, correction 
due to an accumulated error term, and a recursive computation
of the current value of the statistic. 
 The usual computing formulas were also evaluated in
double precision.  Large errors were noted for some 
calculation using the usual computing formulas.  The most
reliable technique was correction of the initial 
estimate by use of an accumulated error term.  To eliminate
the need for making two passes on the data, 
it was suggested that the initial estimate of the
mean be obtained from a subset of the data.

CACM July, 1966

Neely, P. M.

CA660703 JB March 6, 1978  2:54 PM

1411	5	1411
1411	5	1411
1411	5	1411
1619	5	1411
3166	5	1411
1411	6	1411
1411	6	1411
2731	6	1411
2799	6	1411
3159	6	1411
3167	6	1411