# How to find the Cov(estimated beta0,estimated beta1)?

#### drivesafe

##### New Member
Hi, i wonder how to find the Cov(estimated beta0,estimated beta1)?

Thanks!

#### BGM

##### TS Contributor
I suppose you want to find $$Cov[\hat{\beta}_0, \hat{\beta}_1]$$ which are the estimators in simple linear regression with the traditional set up. I think you only need to know that

$$Cov[aX + b, Y] = aCov[X, Y]$$ and $$Cov[X, X] = Var[X]$$ to calculate the covariance.

#### drivesafe

##### New Member
that's my question.
Sry that i don't know how to type "beta hat"

I will try your way to do that. thanks