Statistics- unbiased estimator

[Roni1985]

Homework Statement

A random sample of size 2, Y₁ and Y₂, is drawn from the pdf

f_Y(y;$$\vartheta$$)=2y*$$\vartheta$$², 0<y< 1/ $$\vartheta$$

What must c equal if the statistic c(Y₁+2Y₂) is to be an unbiased estimator for 1 / $$\vartheta$$

Homework Equations

The Attempt at a Solution

I tried to find the E[c(Y₁+2Y₂)] but don't really know how to reach 1 / $$\vartheta$$

There is also the equation of the Y_max

maybe I should set them equal ? but how to get rid of Y1 and Y2 ?

Thanks.

 

[Roni1985]

oh, I got it :\