The above indicates average student costs during the school year. Interpret the data explaining any abnormalities with possible reasons.

The above graph shows average costs for university students over a four year period. The items measured are food, housing, and books. Beginning with books, it can be seen that the expenses for each of the four years are nearly the same. This can be explained in that a student usually takes a similar number of classes each semester and the book expense would remain nearly steady. Food, also, is nearly equal with a slight increase in the second year and then a decline in years three and four. Perhaps this reflects students who move off campus in their second year and spend more on food than they did while living on campus. Housing costs show a large increase in the third year with a return to slightly lower than first and second year totals for the fourth year. An explanation could be that there was a large increase in the number of students attending the university, thereby causing a temporary price rise in the market for housing.