By Rosemarie Emanuele. In Statistics, the idea of “variance” describes how disperse data points are. Are they all bunched right at the mean, or are they very spread out, with some values much larger than the mean, and other values much lower than the mean? I taught this topic last week, and was able to create a visual (and beyond) image for my students. I entered my classroom stomping snow off my boots as I took off my coat and scarf. I asked them the question; “does anyone even remember the heat of the summer?” A room full of tired students who had driven to school in a storm glared back at me. No, no one seemed to remember the sweltering heat and humidity of the summer that had led to a tornado sweeping through and destroying part of the campus. And so I discussed the idea of variation in weather, as it relates to the calculation of the variance of a data set. Read more...