I use this MS PowerPoint presentation file to kickoff our study of Statistics in my 7th and 8th grade math classes. It reviews the definitions and detailed methods required to calculate the mean, median, mode, range and mean absolute deviation (MAD) of a data set(s). It is a totally animated ppt file and very easy for students to understand. Any of the ppt animations can be modified as desired by the presenter (teacher). It also includes 2 example problems for the students to complete toward the end of the slide pack if desired by the teacher. I have also included a copy of the MAD template I use to organize the data to calculate this parameter and this template is included as the last slide of the attached slide pack. As a side note, I always print out a copy of my ppt files for my students to retain in their math notebooks and to jot notes on while I present the slides.