Consider the following probability mass function of a random variable x

[dylbester]

$p(x) ={p}^{x}*{(1-p)}^{1-x}$
for $x=0.1$
$0$ otherwise

Where $p$ is such that $0<=p<=1$

Question:
Find the mean and variance of $X

 

[I like Serena]

$p(x) ={p}^{x}*{(1-p)}^{1-x}$
for $x=0.1$
$0$ otherwise

Where $p$ is such that $0<=p<=1$

Question:
Find the mean and variance of $X$

Hi dylbester! Welcome to MHB! (Smile)

That doesn't seem to be a proper probability mass function.
The sum of $p(x)$ for all values of $x$ is supposed to be $1$.
Since there is only one value for $x$, which is $0.1$, that should mean that $p(0.1)=1$, but that is not the case for any choice for $p$.

Anyway, if there is only one value for $x$, the mean will have to be that value.
And the deviation of that mean can only be $0$, so the variance will then have to be $0$.