Category of performance
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Typical response
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The student needs significant instruction
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Students calculate a single statistic (e.g., mean or median response time). They recommend one ambulance service over the other on the basis of a comparison of this single statistic even though the mean difference is only .2 minute, not significant for making a policy recommendation. The analysis of the data ignores all other variables except response time.
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The student needs some instruction
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Students may calculate measures of center and explore the data with other kinds of analysis (e.g., box plots, stem and leaf plots) but they consider only a single variable - the response times of the two ambulance services. They demonstrate some ability to use their statistical "toolkit" but the analysis is not connected to the real-world context of the problem and the argument is weak.
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The student's work needs to be revised
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Students select appropriate variables for analyzing the data (e.g., response time in relation to time of call), make appropriate calculations, use appropriate graphical representations, and make a reasonable recommendation based on their analysis. There may be errors in the calculations and in the graphs. However, students do not fully interrogate the data set, thereby not ruling out other possible salient relationships (e.g., response time in relation to day of the call). The recommendations follow from the analysis but the report may lack clarity and thoroughness.
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The student's work meets the essential demands of the task
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Students select appropriate variables for sorting, analyzing and representing the data. Students consider a number of relationships and use a variety of analytic tools to fully interrogate the data set. Their recommendations follow from and are supported by their analysis of the data.
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