Math Help - probability distribution ...

1. probability distribution ...

Hello,
I face some problem in this question plz try to solve that.
Thanks .

Question:
Suppose is a random variable best described by a probability distribution given as:f(x)1/25 , 20 less than equal x less than equal 45.

Find the Expected value of X.

2. Originally Posted by m777
Hello,
I face some problem in this question plz try to solve that.
Thanks .

Question:
Suppose is a random variable best described by a probability distribution given as:f(x)1/25 , 20 less than equal x less than equal 45.

Find the Expected value of X.
Please try to type the question more carefully.

"Suppose X is a random variable best described by a probability distribution given as:

f(x) = 1/25 , 20 <= x <= 45.
f(x) = 0 otherwise"

Then $X$ has a uniform distribution on $[20, 45]$, or $X \sim U(20, 45)$. Now we
can calculate the mean as:

$
\bar{x} = \int_{20}^{45} x f(x) dx
$

or we can use the fact that we know that the mean is the midpoint of the
interval or: $32.5$

RonL