|
Note : r is also known as product-moment coefficient of correlation.
OR r = 
OR r = 
Now covariance of x and y is defined as
Example Calculate
the coefficient of correlation between the heights of father and his son
for the following data.
|
Height
of father (cm):
|
165
|
166
|
167
|
168
|
167
|
169
|
170
|
172
|
|
Height of son (cm):
|
167
|
168
|
165
|
172
|
168
|
172
|
169
|
171
|
Solution: n = 8 ( pairs of observations )
|
Height of
father
xi
|
Height of
son
yi
|
x = xi-x
|
y = yi-y
|
xy
|
x2
|
y2
|
|
165
|
167
|
-3
|
-2
|
6
|
9
|
4
|
|
166
|
168
|
-2
|
-1
|
2
|
4
|
1
|
|
167
|
165
|
-1
|
-4
|
4
|
1
|
16
|
|
167
|
168
|
-1
|
-1
|
1
|
1
|
1
|
|
168
|
172
|
0
|
3
|
0
|
0
|
9
|
|
169
|
172
|
1
|
3
|
3
|
1
|
9
|
|
170
|
169
|
2
|
0
|
0
|
4
|
0
|
|
172
|
171
|
4
|
2
|
8
|
16
|
4
|
|
Sxi=1344
|
Syi=1352
|
0
|
0
|
Sxy=24
|
Sx2=36
|
Sy2=44
|
Calculation:
|
Index
6.
1 Introduction
6.
2 Correlation
6.
3 Types of Correlation
6.
4 Degrees of Correlation
6. 5 Methods of determining
correlation
6.
6 Coefficients of Correlation for Bivariate Grouped Data
6.
7 Probable Error
6.
8 Rank Correlation Coefficient
6.
9 Linear Regression
Chapter 7
|
