Download Regression

Regression
Regression Equation
~
y  a  bx
where
a  y  bx
and
b


 xx yy

 xx

2

Nitrogen / Corn Example
2300
b=
 .43
5400
a = 50 - (.43)(50) = 50-21.5 = 28.5
Nitrogen / Corn Example
Y
70
1
50
30
10
.43
Slope
28.3
Intercept
X
10
30
50
70
90
Nitrogen / Corn Example
Nitrogen Application
35 Pounds
~
y = a + b(35)
~
y = 28.5 + (.43)(35)
~
y = 28.5 + 15.05
~
y = 43.6 estimated bushels of corn
Standard Error of the
Estimate
(x
x)(y
y)

2
 (y - y) 2
(x - x)

Syx =
n -2






2
Nitrogen / Corn Example
Standard Error of the Estimate
5290000
1000 
5400
S yx 
3
20. 67

 6. 79  2. 6
3
Normal Distribution
34.13%
13.59%
2.27%
34.13%
13.59%
2.27%
-3S -2S -1S 0S +1S +2S +3S
35.8 38.4 41.0 43.6 46.2 48.8 51.4