I'm going to upload the whole Basic Statistics Lecture series from Descriptive Statistics to Inferential Statistics.
Here's the Third Statistics Powerpoint Lecture
Statistics Lecture three
In this Powerpoint topics covered are: Measures of central tendency, Measures of Variation and Measures of Location
Each topic is summarized and easier to understand rather letting your students read the statistics book. clear examples are given and at the end of each lecture a short exercises is provided for check-up learning of your student.
This powerpoint lecture is animated, and answers in each exercises is provided.
I hope this will help your math class :)