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Regression
Regression means
1.
Correlation is the relationship
going back and it is a
between two or more variables,
which vary in sympathy with the mathematical measure
other in the same or the opposite showing the average
relationship between
direction.
two variables
2.
Both the variables X and Y are
Here X is a random
random variables
variable and Y is a
fixed variable.
Sometimes both the
variables may be
random variables.
It indicates the causes
3.
It finds out the degree of
and effect relationship
relationship between two
between the variables
variables and not the cause and
and establishes
effect of the variables.
functional relationship.
236 4. It is used for testing and
verifying the relation between
two variables and gives limited
information. 5. The coefficient of correlation is
a relative measure. The range of
relationship lies between –1 and
+1 6. There may be spurious
correlation between two
variables.
It has limited application,
because it is confined only to
linear relationship between the
variables. 7. 8. It is not very useful for further
mathematical treatment. 9. If the coefficient of correlation is
positive, then the two variables
are positively correlated and
viceversa. Besides verification it
is used for the
prediction of one
value, in relationship
to the other given
value.
Regression coefficient
is an absolute figure. If
we know the value of
the independent
variable, we can find
the value of the
dependent variable.
In regression there is
no such spurious
regression.
It has wider
application, as it
studies linear and nonlinear relationship
between the variables.
It is widely used for
further mathematical
treatment.
The regression
coefficient explains
that the decrease in one
variable is associated
with the increase in the
other variable. Exercise – 9
I. Choose the correct answer:
1. When the correlation coefficient r = +1, then the two regression
lines
a) are perpendicular to each other
b) coincide
c) are parallel to each other
d) none of these
237 2. If...
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 Winter '08
 Moshiri
 Business

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