What are the roles of middle and supervisory managers?

"The second and third tiers of the hierarchy are called middle management and supervisory (first-line) management, respectively. Middle managers (such as division heads, departmental managers, and regional sales managers) are responsible for beginning the implementation of strategic plans. They design and carry out tactical plans in specific areas of the company. They begin the process of allocating resources to meet organizational goals, and they oversee supervisory managers throughout the firm. Supervisors, the most numerous of the managers, are at the bottom of the managerial pyramid. These managers design and carry out operational plans for the ongoing daily activities of the firm. They spend a great deal of their time guiding and motivating the employees who actually produce the goods and services."