Microsoft Office Tutorials and References
In Depth Information
Chapter 11: Frequency Distributions
In this chapter you will find out how to generate frequency distributions and fre-
quency distribution charts from a data set. Frequency distributions enable you to
better understand the data and the way it is arranged rather than just looking at the
data or the statistics. Frequency distribution allows you to see if the data is sym-
metric, skewed, or flat and detect other information that the statistics could provide.
I will use the same data used in Chapter 10; you will find the data in the Excel
file called Chapter 11. I calculated various statistics in Chapter 10 for that same
data. Two important values were found that will help in determining the frequency
distribution range: the lowest and the highest values. The lowest value is 61 and 129
is the highest. See Figure 11.1.
The first step is to create a list of bins in column F, which will be used to establish
the boundaries for the groups I wish to form for the frequency. In other words, each
one of these bins represents the upper limit of the group
s frequency occurrence.
Since I established that the lowest number, or MIN, is 61 and the highest number is
129, I created bins that will encompass this range. I used 70 as the first bin in order to
count all of the numbers/values below 70 (and above 61 the lowest number). I used
130 as the upper limit of the highest group/bin since the largest number found was
1211. The rule of thumb, for frequency distributions, is to find the range of values
(MIN and MAX values) and to create anywhere from 5 to 15 bins. I chose to use
seven bins/groups in this example.
I typed the word Frequency in cell G1. This word will be visible later for my
chart. The results of my frequency calculations are going to be in the range G2:G8.
See Figure 11.1.
FIGURE 11.1 Frequency Bins Are in F2:F8