Chapter 10 Analysis of Variance 397would cause trouble. In any case, eight observations in each group may be
too few to determine whether the normality assumption is violated.Computing the Analysis of Variance
From the histograms, it appears that New York has the highest mean hotel
price. Still, there is some overlap between the New York prices and the others.
Do you think that New York City is signifi cantly more expensive than the other
cities? We’ll soon fi nd out by performing an analysis of variance. To do so,
we’ll have to use the Analysis of Variance command available from the Analy-
sis ToolPak, the statistical add-in supplied with Excel. The Analysis ToolPak
requires that the group values be placed in separate columns. In this workbook,
groups are identifi ed by a category variable, so you’ll have to unstack the price
values on the basis of the City variable, creating four separate price columns.To unstack the Price column:1 Click Manipulate Columns from the StatPlus menu and then click
Unstack Column.
2 Click the Data Values button, and select Price from the range names
list. Click OK.
3 Click the Categories button, select City from the range name list,
and click OK.
4 Deselect the Sort the Columns checkbox.
5 Click the Output button and send the unstacked values to a new
worksheet named Price Data. Click OK.
Figure 10-4 shows the completed Unstack Column dialog box.
Click OK.Figure 10-4
The Unstack
Column
dialog box
Price values will be
placed in separate
columns
each column created
is based on a different
value of the City
variable