# Math Help - Stats Problem....

1. ## Stats Problem....

I have exams comming up, so practice exam is what i am doing.. however they dont give solutions which is a pain.. anyone care to solve this question because i get stuck.. umm at the start?

2. Originally Posted by spn
I have exams comming up, so practice exam is what i am doing.. however they dont give solutions which is a pain.. anyone care to solve this question because i get stuck.. umm at the start?
The random variable $X$ has density:

$
f_X(x) = \left\{ \begin{array}{cc}

x^2, & \mbox{ for } 0 < x < k \\
0, & \mbox{ for } x<0,\mbox{ or } x>k

\end{array}\right.
$

1. Find the constant $k$.

To be a density we need $\int_0^k x^2 dx = 1$, so find the k
which dose this.

3. cheers ... any ideas how to do the rest? stats is not my fortre, i prefer real algebra that dont require guess work H