Which is a discrete random variable?

A bag contains 4 blue marbles and 2 yellow marbles. Two marbles are randomly chosen (the first marble is NOT replaced before dra

VMariaS [17]

Answer:

0.4 = 40% probability that both marbles are blue.

0.0667 = 6.67% probability that both marbles are yellow.

53.33% probability of one blue and then one yellow

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

Step-by-step explanation:

To solve this question, we need to understand conditional probability(for the final question) and the hypergeometric distribution(for the first three, because the balls are chosen without being replaced).

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

Conditional Probability

We use the conditional probability formula to solve this question. It is

$P(B|A) = \frac{P(A \cap B)}{P(A)}$

In which

P(B|A) is the probability of event B happening, given that A happened.

$P(A \cap B)$ is the probability of both A and B happening.

P(A) is the probability of A happening.

What is the probability that both marbles are blue?

4 + 2 = 6 total marbles, which means that $N = 6$

4 blue, which means that $k = 4$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,4) = \frac{C_{4,2}*C_{2,0}}{C_{6,2}} = 0.4$

0.4 = 40% probability that both marbles are blue

What is the probability that both marbles are yellow?

4 + 2 = 6 total marbles, which means that $N = 6$

2 yellow, which means that $k = 2$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,2) = \frac{C_{2,2}*C_{4,0}}{C_{6,2}} = 0.0667$

0.0667 = 6.67% probability that both marbles are yellow.

What is the probability of one blue and then one yellow?

Total is 100%.

Can be:

Both blue(40%)

Both yellow(6.67%)

One blue and one yellow(x%). So

40 + 6.67 + x = 100

x = 100 - 46.67

x = 53.33

53.33% probability of one blue and then one yellow.

If you are told that both selected marbles are the same color, what is the probability that both are blue?

Conditional probability.

Event A: Both same color

Event B: Both blue

Probability of both being same color:

Both blue(40%)

Both yellow(6.67%)

This means that $P(A) = 0.4 + 0.0667 = 0.4667$

Probability of both being the same color and blue:

40% probability that both are blue, which means that $P(A \cap B) = 0.4$

Desired probability:

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.4}{0.4667} = 0.8571$

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

8 0

3 years ago

A line passes trough the point { 0, -3/2} and has a slope of 1/2. what is the equation of the line?

Luden [163]

Solutions: x=1.

Hope this helps!

6 0

3 years ago

hi um can you tell me where i am supposed to put the 2 points? i know that the first one goes on the 0 but where do i but the 2n

Nina [5.8K]

Answer:

114.75

Step-by-step explanation:

You just multiply 25.50 by 4.50 :))

Hope this helps and sorry if I'm wrong.

Have a wonderful rest of your day. <3

8 0

3 years ago

**PLEASE HELP**

zepelin [54]

----------------------------------------------------------
Given information
----------------------------------------------------------
Area = 3x² + 14x + 8
Length = x + 4

----------------------------------------------------------
Formula
----------------------------------------------------------
Area = Length x Width

----------------------------------------------------------
Find Width
----------------------------------------------------------
3x² + 14x + 8 = (x + 4) x width
width = (3x² + 14x + 8) ÷ (x + 4)
width = (x+4)(3x+2) ÷ (x + 4)
width = 3x + 2

----------------------------------------------------------
Answer: The width is 3x + 2 (Answer C)
----------------------------------------------------------

5 0

3 years ago

Ginny earned $49.50 for 6 hours of gardening and $38.60 for 4 hours of babysitting. For which job did she earn more money per ho

Reil [10]

Well you first need to multiply 49.50 times 6 which equals $297. Then $ 38.60 times 4 which equals $154.4. Ginny earned more money for gardening. She got $161.6 more money than in babysitting. I answered this by multiplying the money and hours. And also to see how much more I added the amounts of money for each job Ginny Works for if I did this wrong plz tell me

7 0

3 years ago