franco wanted to know how much fertilizer he should give his cucumber plants to maximize his yield. he used six plants, giving each plant a different amount of fertilizer but carefully made sure that he controlled for other variables which could affect cucumber production. at the end of the summer, he counted the number of cucumbers produced by each of the six plants. the plant with no fertilizer produced two cucumbers. the plant with 100 grams of fertilizer produced three cucumbers. the plant with 150 grams of fertilizer produced seven cucumbers. the plant with 200 grams of fertilizer produced 10 cucumbers. the plant with 250 grams of fertilizer produced seven cucumbers. the last plant had 300 grams of fertilizer and produced six cucumbers.