School Improvement in Maryland
Making Informed Decisions Using Measures of Central Tendency
 
Data Analysis and Probability .
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Objectives
 
  • The students will be able to calculate the mean, median, mode, range, and interquartile range for a set of data; create a box and whisker plot using paper and pencil and technology; and determine which measure of central tendency is the most helpful in a given situation.
     
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Core Learning Goals
 
  • 3.1.2: The student will use the measures of central tendency and/or variability (mean, median, mode, range, interquartile range, quartile) to make informed conclusions
     
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Drill
 
  • NONE
     
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materials
 
  • Graphing calculator
  • .  Print Version: (Acrobat 51k)
    The print version contains all student worksheets and answer keys needed to complete the lesson.
     

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Calculator Skills
 
  • Enter data in a list; calculate the mean, median and range; and create a box and whisker plot
     
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activities
 
  • Drill.
  • Activity - Have students answer the questions about the three box and whisker plots shown on the student sheet. Students may answer the questions individually or in a group. Answers should be discussed as a class.

    The emphasis of this lesson is on choosing the measure of central tendency which most appropriately represents the data. Basically, median works best in most situations because, unlike mean, it is not affected by outliers. For example this set of data: 2, 10, 11, 11, 12 has a median of 11 and a mean of 9.2. Eleven is a better representation of the most typical number in this set. In other instances, the mean and the median may be so close together that either one would be a good representation.

  • Closure - What information does a box and whisker plot show you? How can you use box and whisker plots to make comparisons? Under what circumstances is it better to use the median rather than the mean to represent a set of data? Under what circumstances is it better to use the mean rather than the median to represent a set of data?
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Assessment
 
  • Drill
  • Class discussion
     
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Homework
 
  • NONE
     
Objective Objective Core Learning Goals Core Learning Goals Drill Drill Materials Materials Calculator Skills Calculator Skills Activities Activities Assessment Assessment Homework Homework