Mark's ceramics spent $4000 on a new kiln last year in the belief that it would cut energy usage 25% over the old kiln. this kiln is an oven that turns "greenware" into finished pottery. mark is concerned that the new kiln requires extra labor hours for its operation. mark wants to check the energy savings of the new oven, and also to look over other measures of their productivity to see if the change really was beneficial. mark has the following data to work with: last yearthis yearproduction (finished units)40004000greenware (pounds)50005000labor (hrs)350375capital ($)1500019000energy (kwh)30002600were the modifications beneficial?

Employees at a library check out books to patrons. books have an isbn and a name. the library sometimes has multiple copies of the same book. books have one or more authors. a patron is an individual who has an active (non-expired) library card. for each library card, we store the person's first and last names and their address. for each employee, we store their employee id, current salary, first and last name and their address. we also store the employee id of their current manager. each time we check out a book to a patron we need to store the date of the transaction, the employee who checked out the book to the patron, and the library card of the patron. some employees have library cards. if an employee patron turns in a book late, the fine that they pay is a percentage of their salary. some employees are authors who have library cards—they are allowed to check out as many books as they like.