In a real life situation, several variables are operating. Some variables may be highly correlated among themselves.
FACTOR ANALYSIS
In a real life situation, several
variables are operating. Some variables may be highly correlated among
themselves. For example, if manager of a restaurant has to analyse six
attributes of a new product. He undertakes a sample survey and finds out the
responses of potential consumers. He obtains the following attribute correlation matrix.
Attribute
Correlation Matrix
We try to group the attributes by
their correlations. The high correlation values are observed for the following
attributes:
Attributes
1, 4 with a very high correlation coefficient of 0.95.
Attributes
2, 4 with a high correlation coefficient of 0.85.
Attributes
3, 4 with a high correlation coefficient of 0.85.
As a result, it is seen that not all the attributes are independent. The
attributes 1 and 4 have mutual influence on each other while the attributes 2,
5 and 6 have mutual influence among themselves. As far as attribute 3 is
concerned, it has little correlation with the attributes 1, 2 and 6. Even with
the other attributes 4 and 5, its correlation is not high. However, we can say
that attribute 3 is somewhat closer to the variables 4 and 5 rather than the
attributes 1, 2 and 6. Thus, from the given list of 6 attributes, it is possible
to find out 2 or 3 common factors as follows:
I.
1. The common features of the attributes 1,3,4 will
give a factor
2. The common features of the attributes 2, 5, 6 will
give a factor
Or
II.
1. The common features of the attributes 1,4 will give
a factor
2. The common features of the attributes 2,5,6 will
give a factor
3. the
attribute 3 can be considered to be an independent factor
The factor analysis is a
multivariate method. It is a statistical technique to identify the underlying
factors among a large number of interdependent variables. It seeks to extract
common factor variances from a given set of observations. It splits a number of
attributes or variables into a smaller group of uncorrelated factors. It
determines which variables belong together. This method is suitable for the
cases with a number of variables having a high degree of correlation. In the above example, we would
like to filter down the attributes 1, 4 into a single attribute. Also we would
like to do the same for the attributes 2, 5, 6. If a set of attributes
(variables) A1, A2, …, Ak filter down to an attribute Ai (1 ≤ i ≤ k), we say that these attributes are loaded on the factor Ai or saturated with the factor Ai. Sometimes, more than one factor
also may be identified. Tags : Research Methodology - Factor Analysis And Conjoint Analysis
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