A price floor is imposed when policymakers have studied the effects of the price floor carefully and they recognize that the price floor is advantageous for society as a whole.
Explanation:
Policymakers take into consideration both the sellers and buyers of corn before imposing a price floor which makes it advantageous to both sides.
Again they also take into consideration the economic implications and impact of the corn market before imposing the policy which is why it benefits the society as a whole.