Question
Let X be a discrete random variable whose probability distribution is defined as follows:
$
P(X=x)=\left\{\begin{array}{cl}
k(x+1) & \text { for } x=1,2,3,4 \\
2 k x & \text { for } x=5,6,7 \\
0 & \text { otherwise }
\end{array}\right.
$
where k is a constant
Find:
i. k
ii. E(X)
iii. Standard deviation of X.
$
P(X=x)=\left\{\begin{array}{cl}
k(x+1) & \text { for } x=1,2,3,4 \\
2 k x & \text { for } x=5,6,7 \\
0 & \text { otherwise }
\end{array}\right.
$
where k is a constant
Find:
i. k
ii. E(X)
iii. Standard deviation of X.