#251lev x in c1, Prob in c2, xP in c3, xsqP in c4. 
sum c2
let c3 = c1 * c2
let c4 = c1 * c3
name k1 'sumP'
let k1 = sum(c2)
name k2 'sumxP'    #mean
let k2 = sum(c3)
name k3  'sxsqP'  #EV of xsq.
let k3 = sum(c4)
name k4 'var'
let k4 = k2 * K2
let k4 = k3 - k4
print k1- k4
print c1 - c4
end