




Massachusetts Comprehensive Assessment System
2014, Grade 10 Mathematics
Question 21: OpenResponse 

Reporting Category: Statistics and Probability Standard: 10.D.2  Approximate a line of best fit (trend line) given a set of data (e.g., scatterplot). Use technology when appropriate. Standard: Mathematics.S.ID.2.06  Represent data on two quantitative variables on a scatter plot, and describe how the variables are related.* 
The table below shows the number of years of work experience and the yearly salary, in thousands of dollars, of 8 people who have the same job. Years of Experience and Yearly Salary Years of Experience, x  0  0  5  5  10  10  20  20  Yearly Salary, y (in thousands of dollars)  25  30  35  40  50  55  70  75  On the grid in your Student Answer Booklet, copy the title, the axes, and the labels exactly as shown below.  On the grid you copied into your Student Answer Booklet, make a scatterplot using the data from the table.
 Draw a line of best fit for the data on the scatterplot you made in part (a).
 Use the line of best fit you drew in part (b) to predict the yearly salary, in thousands of dollars, for a person who has the same job and 15 years of work experience. Show or explain how you got your answer.
 Write an equation that represents the line of best fit you drew on the scatterplot. Show or explain how you got your answer.

Scoring Guide and Sample Student Work Select a score point in the table below to view the sample student response.
Score  Description 
4 
The student response demonstrates an exemplary understanding of the Statistics and Probability concepts involved in representing data on two quantitative variables on a scatterplot and describing how the variables are related. The student creates a scatterplot from a set of data, makes a prediction based on the line of best fit, and writes an equation representing the line of best fit. 
4 
3 
The student response demonstrates a good understanding of the Statistics and Probability concepts involved in representing data on two quantitative variables on a scatterplot and describing how the variables are related. Although there is significant evidence that the student was able to recognize and apply the concepts involved, some aspect of the response is flawed. As a result the response merits 3 points. 
2 
The student response demonstrates a fair understanding of the Statistics and Probability concepts involved in representing data on two quantitative variables on a scatterplot and describing how the variables are related. While some aspects of the task are completed correctly, others are not. The mixed evidence provided by the student merits 2 points. 
1 
The student response demonstrates a minimal understanding of the Statistics and Probability concepts involved in representing data on two quantitative variables on a scatterplot and describing how the variables are related. 
0 
The student response contains insufficient evidence of an understanding of the Statistics and Probability concepts involved in representing data on two quantitative variables on a scatterplot and describing how the variables are related to merit any points. 
Note: There are 2 sample student responses for Score Point 4.
Grade 10 Mathematics
 Question 17: Number and Quantity
 Question 20: Geometry
 Question 21: Statistics and Probability
 Question 36: Algebra and Functions
 Question 41: Geometry
 Question 42: Algebra and Functions
Return to the MCAS 2014 Student Work Directory
Last Updated: January 4, 2019


