XtransX to the minus one X transpose Y

X trans X to the minus one

X transpose Y

I said X trans X to the minus one

X transpose Y

you know that beta hat

is calculated like that

they call it OLS

when you want to regress

it's a fitting tool

that will give to you

the lowest RSS

yes that's the OLS

X trans X to the minus one

X transpose Y

I said X trans X to the minus one

X transpose Y

you know that beta hat

is calculated like that

Ordinary but rather neat

For ease of use it just can't be beat

A simple formula

and the calculation's complete

And you will find it BLUE

when all the assumptions are true

X trans X to the minus one

X transpose Y

I said X trans X to the minus one

X transpose Y

you know that beta hat

is calculated like that

they call it OLS

when you want to regress

it's a fitting tool

that will give to you

the lowest RSS

yes that's the OLS