Contents
[hide]Practice Problem: normalizing the probability mass function of a continuous random variable
A random variable X has the following probability density function:
$ f_X (x) = \left\{ \begin{array}{ll} k, & \text{ if } a\leq x \leq b,\\ 0, & \text{ else}, \end{array} \right. $
where k is a constant. Compute the mean of X.
You will receive feedback from your instructor and TA directly on this page. Other students are welcome to comment/discuss/point out mistakes/ask questions too!
Answer 1
The mean of a random variable is defined as:
$ \int \! x*f_X(x) \, \mathrm{d}x. $
Since the probability density function is k on the interval a to b and zero everywhere else, we can simply write:
$ => \int_a^b \! x*k \, \mathrm{d}x. $
Thus solving we get
$ = 1/2x^2k|_a^b $
$ = \frac{k}{2}(b^2-a^2) $
Answer 2
Write it here
Answer 3
Write it here.
