[question revoved by admin]
I am not sure what formula Elans used… isn’t the formula that should be used is below?
avgVariance*[(1-correlation)/n +correlation] ?
according to me the answer was below
for A 0.22 * ( (1-0.15)/10 +0.15) = 0.0517
for B 0.22 * ( (1-0.15)/200 +0.15) = 0.0339