A question which straight out of a textbook (or from a homework sheet) always stands out a mile - especially if it's in the wrong section! (This belongs in 'History'). You're meant to be doing your own research, not trying to get others to do your work for you!
If you'd have simply Googled 'speenhamland', you'd have found plenty of relevant information. On this occasion, I'll give you a helping hand by telling you that the information you require in on this page:
http://www.victorianweb.org/history/poorlaw/sp een.html
(2nd paragraph below the table of prices).
Chris