TYPICAL HISTOGRAM SHAPES
TYPICAL HISTOGRAM SHAPES AND WHAT THEY MEAN Normal Distribution A common pattern is the bell-shaped curve known as the "normal distribution." In a normal or "typical" distribution, points are as likely to occur on one side of the average as on the other. Note that other distributions look similar to the normal distribution. Statistical calculations must be used to prove a normal distribution. It's important to note that "normal" refers to the typical distribution for a particular process. For example, many processes have a natural limit on one side and will produce skewed distributions. This is normal—meaning typical—for those processes, even if the distribution isn’t considered "normal." Skewed Distribution The skewed distribution is asymmetrical because a natural limit prevents outcomes on one side. The distribution’s peak is off center toward the limit and a tail stretches away from it. For example, a distribution of analyses of a very p...