Consider the following probability mass function of a random variable x

In summary, the probability mass function given is not a proper one and the mean and variance for the given $x$ value and range of $p$ are not meaningful.
  • #1
dylbester
4
0
$p(x) ={p}^{x}*{(1-p)}^{1-x}$
for $x=0.1$
$0$ otherwise

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

Question:
Find the mean and variance of $X
 
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  • #2
dylbester said:
$p(x) ={p}^{x}*{(1-p)}^{1-x}$
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 $0$.
 

FAQ: Consider the following probability mass function of a random variable x

What is a probability mass function?

A probability mass function is a mathematical function that gives the probability that a discrete random variable takes on a specific value. It maps each possible value of the random variable to its corresponding probability.

What does it mean to "consider" a probability mass function?

To "consider" a probability mass function means to analyze and think about the characteristics and implications of the function. This could involve calculating probabilities, graphing the function, or making comparisons to other functions.

How is a probability mass function different from a probability density function?

A probability mass function is used for discrete random variables, meaning the possible values the variable can take on are countable and finite. A probability density function, on the other hand, is used for continuous random variables, meaning the possible values are infinite and not countable.

What does it mean if the values in a probability mass function are non-negative and add up to 1?

If the values in a probability mass function are non-negative and add up to 1, it means that the function follows the two fundamental properties of a probability distribution: all probabilities must be non-negative and the sum of all probabilities must equal 1. This ensures that the function accurately describes the likelihood of all possible outcomes of the random variable.

How can a probability mass function be used in practical applications?

A probability mass function can be used in practical applications to calculate the likelihood of certain events occurring, to make predictions, and to analyze data. It is commonly used in fields such as statistics, economics, and finance to model and understand random phenomena.

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