In order to estimate the mean annual family income for familiesresiding in a particular census area, Mr. Smith has interviewed asample of 600 families and found the average annual family incometo be $6000. Independently, Mr. Jones has taken a sample of 400families in the same area and found the average annual familyincome to be $6,400. Are each of these estimates unbiased? Howwould you combine these two estimates to obtain a single unbiasedestimate of smaller variance? Explain. What is the new estimate youobtain?

 In order to estimate the mean annual family income for families
residing in a particular census area, Mr. Smith has interviewed a
sample of 600 families and found the average annual family income
to be $6000. Independently, Mr. Jones has taken a sample of 400
families in the same area and found the average annual family
income to be $6,400. Are each of these estimates unbiased? How
would you combine these two estimates to obtain a single unbiased
estimate of smaller variance? Explain. What is the new estimate you
obtain?