School Improvement in Maryland
Variability & Data Sets
Data Analysis and Probability .

  • The student will determine the affect that variability in data has on the mean and median.
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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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  • Calculate the mean and the median for each date set. Discuss why your values make sense for the given data.
    1. 3, 4, 50, 60, 70
    2. 30, 40, 50, 60, 70
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  • Activities: "Box and Whisker Plots and Measures of Central Tendency"
  • Additional Problems
  • Answer Keys
  • Graphing calculators
  • .  Print Version: (Acrobat 16k)
    The print version contains all student worksheets and answer keys needed to complete the lesson.

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Calculator Skills
  • Enter data into a list.
  • Create a box an whisker plot and use the trace feature to determine the five-number summary.
  • Calculate the mean and median.
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  1. Drill. Have the students work in pairs to complete this drill. Students should remember that the mean is the numerical average, and the median is simply the middle number. After the pairs have had a chance to discuss the questions let the students explain to the class why their answers make sense. Answers will vary, but you should expect students to notice that the second data set is symmetrical or has numbers equal distance from the middle number while the first data set has two values that are way to the left of the middle number.
  2. Exploration - Have students work with their group or with a partner to complete "Box and whisker Plots and Measures of Central Tendency". Calculators should be available for the students to use. Some students may want to actually plot the boxplots to see these screens on their on calculator. While the students are working circulate to check on their progress, prompt their thinking through leading questions, and give them a chance to ask you questions.
  3. Class Discussion - After most students have completed this activity have a class discussion. This gives you the opportunity to check to make sure that all groups understand the concept of the lesson. See the answer key for the major points that students should bring up during this discussion.
  4. Additional problems - These problems are provided for you to use in any one of a variety of ways such as homework, an individual check for understanding, review, or quiz.
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  • Drill
  • Class discussion
    Group work
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  • NONE
Objective Objective Core Learning Goals Core Learning Goals Drill Drill Materials Materials Calculator Skills Calculator Skills Activities Activities Assessment Assessment Homework Homework