Do you remember in Chapter 2, The Shape of Data, when we described the normal distribution and how ubiquitous it is? The behavior of many random variables in real life is very well described by a normal distribution with certain parameters.
The two parameters that uniquely specify a normal distribution are µ (mu) and σ (sigma). µ, the mean, describes where the distribution's peak is located and σ, the standard deviation, describes how wide or narrow the distribution is.
Figure 4.3: Normal distributions with different parameters
The distribution of heights of American females is approximately normally distributed with parameters µ= 65 inches and σ= 3.5 inches:
Figure 4.4: Normal distributions with different parameters
With this information, we can easily answer questions about how probable it is to choose, at...
