Paper 4: Fundamentals of Business Mathematics & Statistic

FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 6.25

Regression equation of Y on X
Y Y b (x x)− = YX −

Where YX 2
b XY
= x

bYX =^268222 =1.21

Putting the value of bYX in above equation & also put Y 20 & X 16= =

Y - 20 = 1.21(X - 16)

Y - 20 = 1.21X - 1.21X16

Y - 20 = 1.21X -19.36

Y = 1.21X -19.36+ 20

Y = 1.21X +0.64

6.2.7. METHOD III WHEN DEVIATIONS ARE TAKEN FROM ASSUMED MEAN
In case the actual mean of the respective series are not an integer but are in decimals, it becomes
cumbersome to calculate deviations from actual mean as all the values so calculated would also be in
points. In such a case deviations are taken from assumed mean to simplify the calculations.
Regression equation of X on Y is given by
X X b (Y Y)− = XY −

( )

XY X Y X 2 Y

2 Y

Y

Whereb d d d d

d

d N

=^ −

Regression equation of Y on X is given as

Y Y b (X X)− = YX −

( )

YX X Y X Y

2

(^2) X X
d d d d
Whereb
d
d N

−

=^

Example 17 :

Calculate 2 regression equations from the following table—

X 10 12 15 19 15

Y 12 15 25 35 14