Question

1. If n = 5,Σxy=76 ,Σx²= Σy² =90, Σx=20=Σy then covariance=…..​

Answer 1

Answer:

Given that: n=10

∑x=50,∑y=−30

∑x  

2

=290,∑y  

2

=300,

∑xy=−115

Formula :

=  

n∑x  

2

−(∑x)  

2

 

​  

.  

n.∑y  

2

−(∑y)  

2

 

​  

 

n∑xy−∑x.∑y

​  

 

r=  

10×290−(50)  

2

 

​  

.  

10×300−(−30)  

2

 

​  

 

[10×(−115)]−[50×(−30)]

​  

 

=  

2900−2500

​  

.  

3000−900

​  

 

−1150+1500

​  

 

=  

400

​  

.  

2100

​  

 

350

​  

 

=  

20×10  

21

​  

 

350

​  

=  

4  

21

​  

 

7

​  

 

=0.381.