Score Level 1 Anchor Paper

This response demonstrates little application of a reasonable strategy. The representation in the form of an equation is correct (y= -201x+809). The student has not responded to the second, third, or fourth parts of the question. This response demonstrates a minimal understanding and analysis of the problem.

Score Level 1 Anchor Paper

This response demonstrates little application of a reasonable strategy. The student describes the change in value of a computer (The first year the computer costs $180 less than when it first came out. After the first year the cost goes down by $210 each year). The student has not responsed to the first, second, or third parts of the question. The student states that the equation would not be a good prediction model and the justification supports the solution (because you would go into negative numbers and the computer company would owe you money). This response demonstrates a minimal understanding and analysis of the problem.

Score Level 2 Anchor Paper

This response demonstrates an incomplete application of a reasonable strategy. The representation in the form of an equation is correct (y= -201x+809). The student has not responded to the second or third parts of the question. The student states that the equation would not be a good prediction model and the justification supports the solution (the computars value will be in the negitives and you can't have a negitive amount of money when you are talking about value). This response demonstrates a conceptual understanding and analysis of the problem.

Score Level 2 Anchor Paper

This response demonstrates an incomplete application of a reasonable strategy. An equation is not provided. A slope is not given but the contextual meaning is complete (how much the value decreases each year). The age of a computer valued at $300 is correct (about 2½ years old) and the explanation supports the solution (At 3 years old its $200 and at 2 years it was about $400 so $300 is in the middle of 2 and 3 years and that's 2½). The student states that the equation would not be a good prediction model and the justification supports the solution (according to the equation and graph you will have to pay someone to buy your computer. The computer will be worth a negative amount). This response demonstrates a conceptual understanding and analysis of the problem.

Score Level 3 Anchor Paper

This response demonstrates application of a reasonable strategy that leads to some correct solutions within the context of the problem. The representation in the form of an equation is correct (809-201x =y). The slope of the equation, with the inclusion of the variable x, is essentially correct (201x). The contextual meaning is complete (a computer loses 201$ value each year). The age of a computer valued at $300 is correct (about 2½ years), but an explanation is not provided. The student states that the equation would not be a good prediction model and the justification supports the solution (its reached negative by then). This response demonstrates a clear understanding and analysis of the problem.

Score Level 3 Anchor Paper

This response demonstrates application of a reasonable strategy that leads to some correct solutions within the context of the problem. The representation in the form of an equation is correct (y= -201x+809). The slope of the equation is correct (-201) and the contextual meaning is complete (it represents the amount that the value decreases for each year the computer ages). The age of a computer valued at $300 is correct (about 2.5 years old). The explanation supports the solution (I determined this by plugging in 300 for y [value] and solving for x [number of years old] to find that when the computer is worth $300 it is about 2.5 years old). The student states that the equation would be a good prediction model. Although the justification is feasible (since it has decreased at a steady rate for 3 years, it is reasonable to assume that it will continue at the same rate. So if we plug in 6 for x, and solve for y, it is reasonable to assume that we will end up with the likely value in 6 years), the student is incorrect because this strategy would result in a negative outcome. This response demonstrates a clear understanding and analysis of the problem.

Score Level 4 Anchor Paper

This response demonstrates application of a reasonable strategy that leads to correct solutions within the context of the problem. The representation in the form of an equation is correct (y= -201x+809). The slope of the equation is correct (-201) and the contextual meaning is complete (It means that each year the value of the computer drops $201). The age of a computer valued at $300 is correct (2.53 years old) and the explanation is clearly presented and fully developed. The student replaces y in the equation with 300 and solves for x. The student states that the equation would not be a good prediction model and the justification is fully developed. The student replaces x in the equation with 6, solves for y and writes (according to the line of best fit the computer would be worth negative amount of money). This response demonstrates a complete understanding and analysis of the problem.

Score Level 5 Anchor Paper

This response demonstrates application of a reasonable strategy that leads to correct solutions within the context of the problem. The representation in the form of an equation is correct (y= -201x+809). The slope of the equation is correct (-201) and the contextual meaning is complete (the value of a computer goes down $201 per year). The age of a computer valued at $300 is correct (two years and a half) and the explanation is clearly presented and fully developed. The student replaces y in the equation with 300, solves for x and writes (I put in the cost of the computer for y because its the total cost. Then subtracted the 809 + divided that by -201). The student states that the equation would not be a good prediction model and the justification is fully developed. The student replaces x in the equation with 6, solves for y and writes (its showing the number as a negative and you cannot pay negative amount of money). The student provides further justification by replacing y in the equation with 0, solving for x and stating (After 4 years, the computer is worth nothing. After that, its all nothing). This response demonstrates a complete understanding and analysis of the problem.