macro
TwoSamplePoisson c1 c2

#This macro reports the p value for the two-sample Poisson test of
#Ho: mu(1) = mu(2) versus Ha: mu(1) <> mu(2). c1 and c2 are the counts
#from the two independent treatment groups and it is assumed that they
#are drawn using the same size inspection unit. Results from the large
#sample approximation method and the binomial method are reported. The
#F method in Kanji is equivalent to the binomial method.

#See www.ucs.louisiana.edu/~kxk4695/TwoPoisson.pdf for binomial method.
#See http://helios.bto.ed.ac.uk/bto/statistics/tress10.html for LS method.
#See Kanji, 100 Statistcal Tests, Sage Publications, 1999 for the F method.

#Example calling statement:
#   mtb > %twosamplepoisson 3 8

#Rev. (3/2/05, PGM) Wrote original code for LS and binomial methods in V14.

#Copyright (c) 2005 Mathews Malnar and Bailey, Inc.

#Mathews Malnar and Bailey, Inc.
#217 Third Street, Fairport Harbor, OH 44077
#Phone: 440-350-0911
#Fax: 440-350-7210f
#E-mail: pmathews@apk.net, paul@mmbstatistical.com
#Web: www.mmbstatistical.com

#This macro may contain errors or report erroneous results. MM&B Inc. take no
#responsibility for the use or misuse of this macro.

mconstant c1 c2 c csum pLS pbinom z

#By large-sample approximation:
if c1 < c2
   let c = c1
else
   let c = c2
endif

let csum = c1+c2
let z = ((c-csum/2)+0.5) / sqrt(csum/4)		#with continuity correction
cdf z pLS
let pLS = 2*pLS					#two-tailed test
if pLS > 1
   let pLS = 1
endif

#By binomial method:
cdf c pbinom;
   binomial csum 0.5.
let pbinom = 2*pbinom
if pbinom > 1
   let pbinom=1
endif

print pLS pbinom

endmacro