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Uniform Distributions

Figure 15.5 Uniform Distributions

Normal Distributions

Also known as bell curves, normal distributions are data sets whose member data are
weighted toward the center (or median value). When graphed, the shape of the "bell" of
normally distributed data can vary from tall and narrow to short and squat, depending on
the standard deviation of the data set. The smaller the standard deviation, the taller and
more narrow the "bell." Statistically speaking, most measurements of human variance
result in data sets that are normally distributed. As it turns out, end-user response times
for Web applications are also frequently normally distributed.