Find the cumulative distribution function

In summary, the homework statement is that there is a random variable that takes on 3 values with probabilities. The random variable is x and it is modeled by a binomial distribution. The binomial distribution has a mean and a cumulative distribution function.
  • #1
maria_01
3
0

Homework Statement


The random variable x takes on the values 1, 2, or 3 with probabilities (1 + 3k)/3, (1 + 2k)/3, and (0.5 + 5k)/3, respectively.


Homework Equations



i. Find the appropriate value of k.
ii. Find the mean.
iii. Find the cumulative distribution function.


The Attempt at a Solution

 
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  • #2
maria_01 said:

Homework Statement


The random variable x takes on the values 1, 2, or 3 with probabilities (1 + 3k)/3, (1 + 2k)/3, and (0.5 + 5k)/3, respectively.


Homework Equations



i. Find the appropriate value of k.
ii. Find the mean.
iii. Find the cumulative distribution function.


The Attempt at a Solution


As per the guidelines of the forum, you must show your own attempts (some work) before people help you out. It's to make sure we are helping and not doing all the work (and you will truly learn only if you do part of the work yourself).

As a hint for the first question: what should be the sum of the probabibilities of all the possible outcomes?
 
  • #3
The the sum of the probabibilities is 1.
 
  • #4
And so k is what/satisfies what?
 
  • #5
I'm an IT person clueless of statistics. I took an online course and now struggling to understand. If you can help that be great.

Also if I knew how to do it, I wouldn't be asking for help. My attention is not to just get the answers but atleast know which formulas to use and how to imply them. I"m really stuck at cumulative distribution function.
 
  • #6
maria_01 said:
Also if I knew how to do it, I wouldn't be asking for help. My attention is not to just get the answers but atleast know which formulas to use and how to imply them. I"m really stuck at cumulative distribution function.

The rules are, you must show some work! No one is COMPLETELY clueless on a problem. You knew the probabilities summed to 1, so your not completely clueless. Now if you know that the probabilities have to sum to 1, then this should be nothing more than an algebra problem for part A.

If the probabilities sum to 1, what must k be?
 
  • #7
maria_01 said:
I'm an IT person clueless of statistics.

THe first part is nothing to do with stats - you have 3 numbers that sum to 1. The second two parts are just plugging numbers into a formula.
Start with the definitions always.
 

Related to Find the cumulative distribution function

What is a cumulative distribution function?

A cumulative distribution function (CDF) is a mathematical function that represents the probability of a random variable taking on a certain value or falling within a certain range. It is used to determine the likelihood of an event occurring based on the probability distribution of the random variable.

How is a cumulative distribution function different from a probability distribution function?

A probability distribution function (PDF) gives the probability of a specific outcome or value of a random variable occurring. A cumulative distribution function, on the other hand, gives the probability of a random variable falling below a certain value.

What is the purpose of finding the cumulative distribution function?

The cumulative distribution function is useful in analyzing and understanding probability distributions. It allows us to determine the probability of a random variable falling within a certain range, which is important in making predictions and decisions based on data.

How do you find the cumulative distribution function?

To find the cumulative distribution function, you must first determine the probability distribution function of the random variable. Then, you can use integration or summation to find the cumulative probabilities for each possible outcome or range of values.

What are some applications of the cumulative distribution function?

The cumulative distribution function has many practical applications in fields such as statistics, finance, and engineering. It can be used to model and analyze real-world phenomena, make predictions, and evaluate risk. In finance, it is commonly used to calculate the probability of a stock price falling below a certain level. In engineering, it can be used to determine the likelihood of a product failing under certain conditions.

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