1. Lesson Topic: The Mean Absolute Deviation (MAD) Lesson Objective: I can…  I can calculate the mean absolute deviation (MAD) for a given data set.  I can interpret the MAD as the average distances of data values from the mean.

2. Review  What is variability?  What does a distribution that has no variability look like?  Little?  A lot?  The spread of data from the mean  All data points are the same  The data points are clustered  The data points are spread far apart

3. Review  In lesson 8, we used dot plots to visually order several data sets from the one with least variability to the one with most variability.  When are deviations negative?  When are deviations positive?  When they are located to the left of the mean.  When they are located to the right of the mean.

4. Mean Absolute Deviation (MAD)  The sum of the absolute values of the deviations (absolute deviations) divided by the number of deviations  Essentially, we are finding the mean of the absolute deviations in the distribution  Is a measure of the amount of variability in a data distribution  Calculate to the nearest tenth

5. Mean Absolute Deviation (MAD)  Tells us the average distance that all the data values are from the mean.  A small MAD indicates that the distribution has very little variability.  A large MAD indicates that the data points are spread far away from the mean.