Assume that the Y -values in the population are related to an auxiliary variable x through the ratio model Yi = βxi + i, for i = 1, 2,...,N, where the random errors i are independent with E( i) = 0 and var( i) = viσ2 R, in which the vi are known and β and σ2 R are unknown constants. A simple random sample of size n is selected. The best linear unbiased predictor of the population total τ is τˆ = Ys + βs, where Ys is the total of the Y -values in the sample and xs is the total of the x-values not in the sample and
When the variance of Yi is proportional to xi, that is, vi = xi, the best linear unbiased estimator β is the ratio estimator
Compute the value of with this estimator with the data in Example 1.
(b) Show that when the variance of Yi is proportional is the mean-of-the-ratios estimator
Compute the value of τˆ with this estimator with the data in Example 1.