Re: How to calculate on-line the SD of a population?

mean mean = mean + dev/n ssq = ssq + dev*(x - mean) Then the usual st.devn. estimate is: sd = sqrt(ssq/(n-1)) If you want an approximately unbiased estimate of the std. devn., use sd = sqrt(ssq/(n-1.5)) -- Alan Miller (Honorary Research Fellow, CSIRO Mathematical & Information Sc

Re: FYI: data sets to check accuracy of stat packages

strangely don't take their own advice for nonlinear regression. -- Alan Miller, Retired Scientist (Statistician) CSIRO Mathematical & Information Sciences Alan.Miller -at- vic.cmis.csiro.au http://www.ozemail.c

Re: convolution of binomials

z-r) where p1 is the first binomial probability, and p2 is the second. The upper & lower limits of summation, l & u, are not necessarily 0 and z but: l = max(0, z-n2) and u = min(z, n1) I hope I have got that right. I doubt if the sum simplifies much. -- Alan Miller, Retired Scientis