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FORMATIVE ASSESSMENT TASK
Instructions for Implementing the Task
This task can be implemented individually, with small groups, or with the whole class.
 The teacher asks the student to complete the problem on the Explain Measures of Variability worksheet.
 The teacher asks followup questions, as needed.
TASK RUBRIC
Getting Started 
Misconception/Error The student is unable to identify key measures of variability. 
Examples of Student Work at this Level The student:
 Does not identify both interquartile range and mean absolute deviation.
 Includes measures that do not describe variability.

Questions Eliciting Thinking Are there any more measures of variability you may have left out?
Do all of these describe the variability of a distribution? 
Instructional Implications Review the vocabulary used to describe measures of center and variability. Clearly distinguish the two types of measures. Explain that both are used to summarize a distribution of values, but they do so in different ways.
Explain that measures of variability provide an indication of how much the data varies in a data set. Review how each of the range, interquartile range, and mean absolute deviation are calculated and explain how each describes or represents the spread in the data. Indicate that measures of spread are typically paired with measures of center to summarize data sets.
Provide data sets with the same centers but different spreads (e.g., a set of math test scores that range from 80% to 90% and a set of math test scores that range from 70% to 100%). Have the student compare the data sets by calculating both a measure of center and a measure of spread. Assist the student in interpreting the measures of spread in relationship to its data set.
Provide opportunities to describe and summarize distributions of data by calculating measures of center and variability. 
Making Progress 
Misconception/Error The student is unable to explain what measures of variability tell you about a set of data. 
Examples of Student Work at this Level The student:
 Describes calculation procedures for measures of variability or provides an example calculation.
 Provides a superficial or circular response (e.g., “measures of variability tell you the variability”).

Questions Eliciting Thinking In general, what does a measure of variability tell you about a set of data?
You did a good job explaining how to do these calculations, but what do these values indicate about a set of data? How do they give you information about a set of data? 
Instructional Implications Explain that measures of variability provide an indication of how much the data varies in a data set. Review how each of the range, interquartile range, and mean absolute deviation are calculated and explain how each describes or represents the spread in the data. Indicate that measures of spread are typically paired with measures of center to summarize data sets.
Provide opportunities to describe and summarize distributions of data by calculating measures of center and variability. 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student:
 Lists both interquartile range and mean absolute deviation.
 Explains that a measure of variability is a single number that describes the spread of data in a distribution.

Questions Eliciting Thinking Why is it useful to know the interquartile range of a data set?
What measure of spread is generally used when the mean is used as a measure of center? When the median is used as the measure of center? 
Instructional Implications Provide the student with the mean, median, mean absolute deviation, and interquartile range of a single data set, and challenge him or her to draw the shape of a distribution that fits the given measures.
Consider implementing MFAS tasks Explain Measures of Center and Compare Measures of Center and Variability (6.SP.1.3). 
ACCOMMODATIONS & RECOMMENDATIONS
Special Materials Needed:
 Explain Measures of Variability worksheet
SOURCE AND ACCESS INFORMATION
Contributed by:
MFAS FCRSTEM
Name of Author/Source: MFAS FCRSTEM
District/Organization of Contributor(s): Okaloosa
Is this Resource freely Available? Yes
Access Privileges: Public
* Please note that examples of resources are not intended as complete curriculum.