A random variable $x$ has the following probability distribution: 

$X=x$	0	1	2	3	4	5	6	7	8
$P(X=x)$	$a$	$3a$	$5a$	$7a$	$9a$	$11a$	$13a$	$15a$	$17a$

Statement I : The value of $\text{'}a\text{'}$ is $\frac{1}{81}$  
Statement II : Mean of random variable $X$ is 6