A farmer has noticed that his soybean plants produce more beans in some years than others. He claims to always apply the same amount of fertilizer to the plants but he suspects the difference in crop yield may have something to do with the amount of water the crops receive. The farmer has observed that the soybeans on his farm usually receive between 0 to 0.5 inches of water per day, but he is unsure of the optimal amount of water with which to irrigate.