Chapter 2: Graphs, Charts, and Tables--Describing Your Data

CHAPTER 2 • GRAPHS, CHARTS, AND TABLES—DESCRIBING YOUR DATA 45
Next, we determine the class width using Equation 2.2. The highest account balance
in the sample is $1,493.00. The minimum is $99.00. Thus, the class width is
1, 493. 00 99.
00
W
10
139.
40
which we round up to $150.00.
Our classes will be
$90–239.99
$240–389.99
$390–539.99
etc.
The resulting histogram in Figure 2.5 shows that the data are centered between
$690 and $840. The customers vary considerably in their credit card balances, but the
distribution is quite symmetrical and somewhat bell-shaped. Capital Credit Union managers
must decide whether the usage rate for the credit card is sufficient to warrant the
cost of maintaining the credit card accounts.
FIGURE 2.5
Excel 2007 Output of
Credit Card Balance
Histogram
Excel 2007 Instructions:
1. Open file: Capital.xls
2. Set up an area on the worksheet for the
bins defined as 239.99, 389.99, etc. up
to 1589.99 Be sure to include a label
such as “Bins.”
3. On the Data tab, click Data Analysis.
4. Select Histogram.
5. Input Range specifies the actual data
values as the Credit Card Account
Balance column and the bin range as the
area defined in Step 2.
6. Put on a new worksheet and include
the Chart Output.
7. Right-mouse-click on the bars and use
the Format Data Series Options to set
gap width to zero and add lines to the
bars.
8. Convert the bins to actual class labels
by typing labels in Column A. Note,
the bin 239.99 is labeled 0-239.99.