In the last session we learnt about how to use proximity
data in Permap using SimilarityList and DissimilarityList. Today we will learn
how attribute data can be used in Permap.
What is an attribute? An attribute is some aspect
of an object. It may be called a factor, characteristic, trait, property,
component, quantity, variable, dimension, parameter etc.
In
attribute mapping, each object is represented by a set of attribute values and
the proximities between objects are calculated from the attribute data using
any of several standard relationships.
The format that needs to be used is:
NOBJECTS=6
Gives the number of objects
in the analysis.
NATTRIBUTES=3
Gives
the number of attribute values for each object.
ATTRIBUTELIST Announces
that attribute values follow.
Attributes
Evaluation Screen
This screen is divided into four parts: Analysis options, Attribute selection, Attribute
fit plot and Notes.
Analysis Option:
It provides five ways to superimpose attribute
gradient vectors on the MDS map. Each option has on-line context-sensitive
information provided in a "Notes" text box at the bottom of the
Attributes menu screen. If no attributes are given in the problem definition,
then the Attributes menu entry is disabled.
Attribute Selection:
It is a box that lists all available attributes.
By highlighting a member of this box you determine which attribute is to be
used for the Attribute Fit plot and for plotting the various on-map gradient
vectors. If you have more than seven attributes you will need to use the right
arrow to highlight the “missing” attribute numbers in the Attribute Selection
List box.
Attribute Fit Plot:
The Attribute Fit plot is a scatter plot that
shows how well one or all of the attributes are described by an optimally
oriented uni-variant gradient running across the map. As usual, the coefficient
of determination, R2, is the key measure. A perfect fit results in R2 = 1,
whereas random behavior causes R2 to approach zero.
The above figure shows that the attributes 1and 2 are
influencing each other. Similarly attribute 4 and 6 influence each other.
Attribute 3 and 5 are opposite in direction. That means they are inversely related
i.e. if attribute 3 improves then attribute 5 reduces.
Here one needs study which attribute needs to be
improved for which store and what needs to be done for the same.
Team A
Ankur Mundra
14009
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