#252-2means		Computes material for hypothesis test of 2 means.
#			Set k201=s1squared, k202=n1, k203=s2squared, k203=n2. 
name k201 's1sq'
name k202 'n1'  
name k203 's2sq'  
name k204 'n2'
let k205=k201/k202	#s1sq/n1
let k206=k203/k204	#s2sq/n2
name k207 'sdbrsq'	#sdbar squared - unequal variances
let k207=k205+k206
name k208 'sdbar'	#sdbar
let k208=sqrt(k207) 
let k209=k207*k207	#numerator for degrees of freedom
let k210=k202-1		#n1 - 1
let k211=k204-1		#n2 - 1
let k214=k210*k201	#(n1 - 1)s1sq
let k215=k211*k203	#(n2 - 1)s2sq
let k217=k214+k215
let k216=k210+k211
name k216 'spsq'
let k216=k217/k216	#sp squared
let k217=1/k202		#1/n1
let k218=1/k204		#1/n2
let k219=k217+k218	#(1/n1) + (1/n2)
let k220=k216*k219	#sdbar sq
name k221 'sdbr1'
let k221 =sqrt(k220)	#sdbar equal variances
let k210=k205*k205/k210	#(s1sq/n1)sq/(n1 - 1)
let k211=k206*k206/k211	#(s2sq/n2)sq/(n2 - 1)
let k212=k210+k211	#denominator for degrees of freedom 
name k213 'df'
name k222 'df1'
let k213=k209/k212	#df
let k222 = k202 + k204 -2	#df for equal
print k201-k222
end