proportional allocation was used in the stratified sample in example 3.2. it was noted, however, that variability was much higher in the west than in the other regions. a. using the estimated variances in example 3.2, and assuming that the sampling costs are the same in each stratum, find an optimal allocation for a stratified sample of size 300. select a stratified random sample of size 300 from the data in the file agpop, using your allocation in part a). b. estimate the total number of acres devoted to farming in the united states, and give the standard error of your estimate. (2pts) c. how does this standard error compare with that found in example 3.2? (1pt)