The department of agriculture in a midwestern state wants to estimate the amount of corn produced in the state that is used to make ethanol. There are 50,000 farms in the state that produce corn. The farms are classified into four groups depending on the total number of acres planted in corn. A random sample of 500 farms is selected from each of the four groups, and the amount corn used to generate ethanol is determined for each of the 2,000 selected farms.
a. What is the population of interest?
b. What is the sampling frame?
c. What type of sampling plan is being used in this study?
d. What biases if any may result from using the data from this study to obtain an estimate of the amount of corn used to produce ethanol?