Probability Mass Function of a Discrete Non-Uniform Distribution

In summary: None-I've understood the PMF by graphing it out, So if the X-axis is the (0,1 ..., 9) and the Y-axis are the probabilities, the height of each X-axis value is its PMF. But I don't understand how the Y-axis probabilities are calculated or would they be 0, 1/9, 2/9..., 1.I've read that the PMF >= 0 and that the sum of the PMF's of all possible values in a distribution should be equal to 1.I've understood the PMF by graphing it out, So if the X-axis is the (0,1 ..., 9)
  • #1
iTee
6
0

Homework Statement



I'm having trouble understanding PMF. We are given a number, say, 927189234.

We need to calculate the PMF of (0, 1, ..., 9) in this distribution.

Homework Equations





The Attempt at a Solution



Calculating the probabilities is easy,

P(9) = 2/9
P(8) = 1/9
.
.
.
P(0) = 0/9

I fail to understand if this is the same as the PMF.

Any help would be greatly appreciated.
 
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  • #2
iTee said:

Homework Statement



I'm having trouble understanding PMF. We are given a number, say, 927189234.

We need to calculate the PMF of (0, 1, ..., 9) in this distribution.

Homework Equations





The Attempt at a Solution



Calculating the probabilities is easy,

P(9) = 2/9
P(8) = 1/9
.
.
.
P(0) = 0/9

I fail to understand if this is the same as the PMF.

Any help would be greatly appreciated.

What do YOU think is meant by the term PMF?

RGV
 
  • #3
-None-
 
Last edited:
  • #4
I've understood the PMF by graphing it out,

So if the X-axis is the (0,1 ..., 9) and the Y-axis are the probabilities, the height of each X-axis value is its PMF. But I don't understand how the Y-axis probabilities are calculated or would they be 0, 1/9, 2/9..., 1.

I've read that the PMF >= 0 and that the sum of the PMF's of all possible values in a distribution should be equal to 1.
 
  • #5
iTee said:
I've understood the PMF by graphing it out,

So if the X-axis is the (0,1 ..., 9) and the Y-axis are the probabilities, the height of each X-axis value is its PMF. But I don't understand how the Y-axis probabilities are calculated or would they be 0, 1/9, 2/9..., 1.

I've read that the PMF >= 0 and that the sum of the PMF's of all possible values in a distribution should be equal to 1.

Exactly!---although very badly worded. (You don't sum the PMFs; there is just one single PMF and it is a table of the probability values; you are not summing different tables, you are just summing the things in a single table.) So the values of the PMF cannot be 0, 1/9, 2/9, ..., 1 because when you sum these you get something much larger than 1. You seem to be confusing PMF and CDF.

RGV
 
  • #6
PMF of 9 is 2/9.
 
Last edited:
  • #7
Yes.

RGV
 
  • #8
So the table of PMF is
{2/9, 2/9, 1/9, 1/9, 1/9, 1/9, 1/9}
?

Thank you.
 
  • #9
iTee said:
So the table of PMF is
{2/9, 2/9, 1/9, 1/9, 1/9, 1/9, 1/9}
?

Thank you.

Not quite; you also need to specify the x values (and you need to include zero). I liked your original description P(0) = 0, P(1) = 2/9, etc. much better. That says it all. Or you could make a table with x values in one column (or row) and P(x) values in the other column (or row).

RGV
 

Related to Probability Mass Function of a Discrete Non-Uniform Distribution

What is a probability mass function (PMF)?

A probability mass function (PMF) is a function that maps each possible outcome of a discrete random variable to its probability of occurrence. It represents the probability distribution of a discrete random variable.

What is a discrete non-uniform distribution?

A discrete non-uniform distribution is a probability distribution where the outcomes are discrete (distinct and separate) and the probabilities associated with each outcome are not equal. This means that some outcomes are more likely to occur than others.

How do you calculate the PMF of a discrete non-uniform distribution?

The PMF of a discrete non-uniform distribution can be calculated by dividing the number of times a specific outcome occurs by the total number of outcomes. This will give you the probability of that outcome occurring.

What is the difference between a discrete non-uniform distribution and a discrete uniform distribution?

The main difference between a discrete non-uniform distribution and a discrete uniform distribution is that the probabilities associated with each outcome in a discrete non-uniform distribution are not equal, while in a discrete uniform distribution, all outcomes have equal probabilities. This means that in a discrete non-uniform distribution, some outcomes are more likely to occur than others, while in a discrete uniform distribution, all outcomes have an equal chance of occurring.

How do you interpret the PMF of a discrete non-uniform distribution?

The PMF of a discrete non-uniform distribution can be interpreted as the likelihood of a specific outcome occurring. The higher the probability associated with an outcome, the more likely it is to occur. Additionally, the PMF can also provide information about the shape and spread of the distribution, such as the most likely outcome and the range of possible outcomes.

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