- #1
Mdhiggenz
- 327
- 1
Homework Statement
The proportion of time x that an industrial robot is in operation during a 40 hour work week is a random variable wth probability density function
f(x)= 2x 0≤x≤1
I already found my E(x) to be 2/3 " Mean" and V(x) to be 1/18 " variance"
Here is where things get confusing for me.
For the robot under study, the profit Y for a week is given by
Y=200*x-60
Find E(Y) and V(Y).
So I found E(Y) to be just y=200(E(x))-60
which makes sense.
But for V(Y)
we have to ignore the constant and sqareroot the first term so it would be
V(Y)=v[200x-60]=2002*v(x) "ignoring the constant"=2002*1/18
I don't understand the logic to computing the variance. Why would we ignore the constant and just square the first term?
Thanks