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Massachusetts Comprehensive Assessment System

2014, Grade 7 Mathematics

  Question 18: Open-Response calculator allowed
Susan put blue tiles, green tiles, and yellow tiles into a bag. All the tiles are the same size and shape. Susan will select one tile from the bag without looking, record its color, and then put the tile back into the bag. She will repeat this experiment 240 times. Based on the number of tiles of each color in the bag, Susan predicted the results shown in the frequency table below.
Predicted Results
 
Color of TileFrequency
blue120
green40
yellow
  1. Based on the table, what is the best prediction for the number of times Susan will select a yellow tile from the bag? Show or explain how you got your answer.
A total of 12 tiles are in the bag.
  1. Based on the table, determine the number of blue tiles, the number of green tiles, and the number of yellow tiles that are in Susan’s bag. Show or explain how you got each of your answers.

Scoring Guide and Sample Student Work
Select a score point in the table below to view the sample student response.

ScoreDescription
4 The student response demonstrates an exemplary understanding of the Statistics and Probability concepts involved in developing a probability model and using it to find probabilities of events. When given the total number of selections and some of the data, the student completes a frequency table and predicts the number of tiles of each color in a bag.
4
3 The student response demonstrates a good understanding of the Statistics and Probability concepts involved in developing a probability model and using it to find probabilities of events. 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 developing a probability model and using it to find probabilities of events. 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 developing a probability model and using it to find probabilities of events.
0 The student response contains insufficient evidence of an understanding of the Statistics and Probability concepts involved in developing a probability model and using it to find probabilities of events to merit any points.

Note: There are 2 sample student responses for Score Point 4.

Grade 7 Mathematics

Question 10: The Number System
Question 18: Statistics and Probability

Return to the MCAS 2014 Student Work Directory



Last Updated: September 04, 2014
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