Note : r is also known as productmoment 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
x_{i}

Height of
son
y_{i}

x = x_{i}x

y = y_{i}y

xy

x^{2}

y^{2}

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

Sx_{i}=1344

Sy_{i}=1352

0

0

Sxy=24

Sx^{2}=36

Sy^{2}=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
