SOAN 3120 Chapter Notes - Chapter 3: Standard Deviation, Quartile, Normal Distribution

• School: University of Guelph
• Department: Sociology and Anthropology
• Course: SOAN 3120
• Professor: Michelle Dumas

Document Summary

Our eyes respond to the areas of bars in a histogram, the bar areas represent proportions of the observations. In moving from histogram bars to a smooth curve, we make a specific choice: we adjust the scale of the graph so that the total area under the curve is exactly 1. The total area represents the proportion 1, that is, all the observations. We can then interpret areas under the curve as proportions of the observations. The curve is now a density curve. A density curve is a curve that: is always on or above the horizontal axis, and, has area exactly 1 underneath it, a density curve describes the overall pattern of distribution. The area under the curve and above any range of values is the portion of all observations that fall in that range. Density curves like distributions come in many shapes: both show the overall shape and the bumps in the long tail.