It would certainly be understandable to associate the term “random sampling” with a Sunday afternoon stroll through the grocery section of Costco. Making a meal out of the treats served in those little paper cups is now part of our cultural norm. What happened with our fourth graders last week, however, was more statistical in nature. After a disheartening attempt to grow cucumbers, these students decided to try planting carrots. Much to their delight, nearly every tiny seed they sprinkled into soil sprouted. So many, that it became obvious some thinning would be necessary. In fact, it appeared that at least half of the seedlings would have to go. While discussing this task at hand, we became curious as to how many seedlings each student would have to pull. (assuming each student would pull the same number) If you have ever thinned seedlings with young fingers you will understand that restraint is a significant factor, so clarity is always a good idea. We quickly concluded that if we were going to calculate how many sprouts would be pulled by each student, we would first need to know how many sprouts we had all together. This would be our “population”. We decided that rather than counting each individual carrot plant we would look at one small patch of the bed, see how many carrots were in that patch, and then determine how many of those patches would fit in our bed. We would then multiply that number by the number of carrots counted in that one patch. It was determined that a six inch square would be a good size and this would be our “sample”. After calculating our total population of carrots, we would divide that number in half since half of the carrots needed to be pulled. We would then divide that number by the number of students to determine how many each student would take out.
If at this point you are starting to lose interest, you would have lots of company from fourth graders in classrooms everywhere who are limited to reading mathematic word problems from a page in a textbook. Try reading aloud some of the above paragraph to a fourth grader and watch as their eyes glaze over. I cannot tell you how different it was to actually do this math problem in the garden. (I could try, but in a few pages your eyes would be the ones glazing over) I can, however, tell you with absolute honesty that this class was having a good time. The best kind of good time. A challenging good time.