FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 6.3980 1500
5 80 300
160 2500 160 500
5
− −
= = −
−
(^220) 0.647
340
=− =
−
( )
X Y X Y
YX 2
2 X
Xd d d d
b N
d d
N−
=
−
( )^2
80 30x50
5
100 30
5−
=
−
(^220220220) 2.75
100 900 100 180 80
5
= − = − =− =
− − −
Example 27 :
Given that ∑X = 120, ∑Y = 432, ∑XY = 4992, ∑X^2 = 1392, ∑Y^2 = 18252 N = 12 Find:
(1) The two regression equations
(2) The regression coefficients
(3) Coefficient of correlation
Solution:
X X^12010
= N 12= =
∑Y Y^43236
= N 12= =
∑
( )
XY 2
2XY X Y
b N
Y
Y N−
=
−
24992 120x432
12
18252 (432)
12