Statistical patterns can be found in nature and society. Their distribution may conform to mathematical models. Thus, if two unbiased dice are rolled a thousand times, the number seven will occur with six times the frequency of two or twelve. The resulting histogram will be symmetrical with one peak where the mean, median and mode coincide. Or take a large sample of adult human beings and measure their height. Most cases will fall between five and six feet with very few less than four or more than seven feet. Because this is a continuous variable, the results can be plotted on a graph to which a curve may be fitted. It too will have a single peak with fantails on the high and low ends. We call this the ‘normal’ distribution or popularly the ‘bell curve.’ For more than a century, statistical inference has largely been based on this curve with its parameters of mean and standard deviation.