Data Analysis with Microsoft Excel: Updated for Office 2007

146 Fundamentals of Statistics

This chart shows us that the distribution of home prices is positively

skewed (as we would expect) for both northeast sector and nonnortheast

sector homes. The primary difference is that in the northeast sector there

are more homes at the high end. By selecting the appropriate chart subtype,

we can switch back and forth between side by side and stacked views of the

histogram; we can even view the histogram in three dimensions.

Working with Stem and Leaf Plots

Stem and leaf plots are another way of displaying a distribution, while at

the same time retaining some information about individual values from the

data sample. The stem and leaf plot originally was used by statisticians as

a quick way of generating a plot of a distribution using only pen and paper,

but still has application even when graphical plots are so readily available.

To create a stem and leaf plot, follow these steps:

1. Sort the data values in ascending order.


2. Truncate all but the fi rst two digits from the values (i.e., change 64,828
   to 64,000, change 14,048 to 14,000, and so forth). The fi rst of the two
   digits is the stem and the second the leaf. In the case of a number like
   64,000, the stem is 6 and the leaf is 4.


3. List the stems in ascending order vertically on a sheet and place a
   vertical dividing line to the right of the stems.

Figure 4-12
Histogram bars
displayed
side by side