Numerical Data Analysis

Advice

• Be sure to group together the median and IQR, and the mean and standard deviation
• Explain that a measure of center is not sufficient to describe data.  A measure of spread is needed in addition.
• Connect numerical concepts to graphics using example data sets and applets or Fathom.
• When covering the sample standard deviation, be prepared for the "why n-1?" question!!! 

Applets

• This applet from the Rossman/Chance collection shows the dotplot of a data set, allows you to guess the mean, median, deviation, and IQR, and the shows the actual values. You can also change the given data or upload your own data.
  

Activities

• Why n-1? You might not have time to do this activity with your students, but if you have never taught statistics before (and especially if you have never taken a statistics course), it is a good idea for you as the instructor to go through it to get a sense of why we divide by n-1.