$Y_1,...,Y_n$ denote a random sample of size $n \geq 4$ from distribution with density function: $f(y)= 4 y^3/\theta^4$, 0
involving an unknown parameter $\theta$, ($\theta>0$). $Y(n)= \max \{ Y_1, \ldots ,Y_n \}$. How would I construct an appropriate pivot using $Y(n)$ and $\theta$?
Also, utilizing the pivot, construct a two-sided 1-alpha confidence interval for $\theta$?