138 Fundamentals of Statistics
This table is a lot easier to interpret than that of Figure 4-4. Looking at the
table, it’s easy to discover that there were only two houses in the sample in
the $140,000–$150,000 price range.STATPLUS TIPS
You can use the Frequency Table command to create tables that
are broken down into categories on the basis of a qualitative
variable. To do so, click the By button in the Frequency Table
dialog box and choose the range name or range reference con-
taining the values of the qualitative variable.
If you forget how the bin counts are determined, place your cur-
sor over the column title for the bin value. A pop-up comment
box will appear indicating the method used.Working with Histograms
Frequency tables are good at conveying specifi c information about a dis-
tribution, but they often lack visual impact. It’s hard to get a good impres-
sion about how the values are clustered from the counts in the frequency
table. Many statisticians prefer a visual picture of the distribution in the
form of a histogram. A histogram is a bar chart in which each bar represents
a particular bin and the height of the bar is proportional to the number of
counts in that bin. Histograms can be used to display frequencies, cumula-
tive frequencies, percentages, and cumulative percentages. Most histograms
display the frequency or counts of the observations.Creating a Histogram
Excel does not have a chart type for the histogram, but you can create one us-
ing either the Data Analysis ToolPak supplied with Excel or using the com-
mand from the StatPlus add-in. Create a histogram of the price data from the
Housing workbook using the StatPlus histogram command.To create a histogram of the home prices:1 Click Single Variable Charts from the StatPlus menu and then click
Histograms.
2 Click the Data Values button and select Price from the list of range names.
As with the Frequency Table command, you can specify the number
and type of bins used to construct the bars of the histogram.