# Types of distribution curves

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A distribution curve is a map of occurrences between (at least) two variables. The curve maps occurrences of something, events--such as flips of a coin--IQ scores or financial worth, for example. There are three general types of distribution curves. The different types reflect different facets of reality. The mathematical means of dealing with these curves are made up of three variables: the mean (or the average of all occurrences), the median (the occurrence exactly in the middle) and the sample size (or n, the number of events considered).

## Normal Distribution

graph image by peter Hires Images from Fotolia.com

This is the most common distribution curve, familiar to nearly all. It deals with many random events over time. It is typified by a small number of occurrences on the extreme right or left of the curve, with the bulk of occurrences happening in the middle. It looks like a big heap. Mathematically, the mean and median are the same. In fact, the closer to median and mean are to each other, the more of a normal curve you have. Random associations will create this curve over time with a large enough sample size. If one is comparing ages (on the y, or vertical axis) to the preference of the colour green (x, or the horizontal axis), then it is likely a normal curve will result.