NCSSM – Carolyn Doetsch , Peter Flanagan-Hyde, Mary Harriso n, Josh Tabor, Chuck Tiberio -- revised Lee Kucera 200 7
1
Rolling Down the River Name: ____________________________
Date: ____
A farmer has just cleared a new field for corn. It is a unique plot of land in that a
river runs along one side. The corn looks good in some areas of the field but
not others. The farmer is not sure that harvesting the field is worth the
expense. He has decided to harvest 10 plots and use this information to
estimate the total yield. Based on this estimate, he will decide whether to
harvest the remaining plots.
Part I.
A. Method Number One: Convenience Sample
The farmer began by choosing 10 plots that would be easy to harvest. They are marked
on the grid below:
X
X
X
X
X
X
X
X
X
X
Since then, the farmer has had second thoughts about this selection and has decided to come to
you (knowing that you are an AP statistics student, somewhat knowledgeable, but far cheaper than a
professional statistician) to determine the approximate yield of the field.
You will still be allowed to pick 10 plots to harvest early. Your job is to determine which of
the following methods is the best one to use – and to decide if this is an improvement over the
farmer’s original plan.
B. Method Number Two: Simple Random Sample
Use your calculator or a random number table to choose 10 plots to harvest. Mark them
on the grid below, and describe your method of selection.
