Probability question ,Random variables and probability distribution

In summary, the problem involves finding the first children's CD out of a box containing 5 indiscernible CDs. The random variable X represents the number of tests needed to find the first children's CD. The possible values of X are 1, 2, 3, and 4. To determine the probability distribution of X, the probability of X=1, X=2, X=3, and X=4 must be calculated. From there, the probability that at least 2 tests were performed can be solved.
  • #1
tj00343
63
0
I'm completely lost on this probability problem,

Homework Statement



A Box contains 5 indiscernible CDs.It is known that among them 2 are for children .So in order to find the first children's CD ,they are tested one after the other (successively ),Denote by X the random variable which represents the number of tests until the first children's cd is spotted

1- List all the possible values of X

2-Determine the probability distribution of X

3- Calculate the probability that at least 2 tests were performed

2. The attempt at a solution

1- x={1 2 3 4 }
2- very lost here
3- I can't solve without part 2

thank you
 
Last edited:
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  • #2
Is this a trick question? They're CDs, so you'll never spot a book. :wink:

You should be able to tell us the probability that X=1.
 
  • #3
vela said:
Is this a trick question? They're CDs, so you'll never spot a book. :wink:

You should be able to tell us the probability that X=1.

You should also be able to tell us the probability that X = 2. After that, you should be able to do X = 3 and X = 4.

RGV
 

1. What is the difference between probability and statistics?

Probability is the measure of the likelihood that an event will occur, while statistics is the collection, analysis, interpretation, and presentation of data.

2. What is a random variable?

A random variable is a numerical quantity whose value depends on the outcome of a random event.

3. What is a probability distribution?

A probability distribution is a mathematical function that describes the likelihood of different outcomes of a random variable in a sample space.

4. How do you calculate the expected value of a random variable?

The expected value of a random variable is calculated by multiplying each possible outcome by its probability and summing the results. It represents the average value of the random variable over a large number of trials.

5. What is the central limit theorem?

The central limit theorem states that as the sample size increases, the distribution of sample means from a population will approach a normal distribution, regardless of the shape of the original population distribution. This allows for the use of normal distribution in statistical inference and hypothesis testing.

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