How Do You Solve These Continuous Probability Problems?

In summary, the conversation discusses finding F(x) for a given function, using F(x) to find probabilities for certain intervals, finding the expected value and standard deviation of X using integrals, and addressing potential mistakes in the formulas provided.
  • #1
noreturn2
25
0

Homework Statement


f(x) = (3/4)(-x^2 + 6x - 8) for 2 < x < 4 (0 elsewhere)

A) Find F(x)

integral 2 to 4 ((3/4)(-x^2 + 6x - 8))dx

B) Use F(x) to find P(3 < X < 3.5)

integral 3 to 3.5 ((3/4)(-x^2 + 6x - 8))dx

11/32

C) Use F(x) to find P(X > 3.5)

1-( P(3 < X < 3.5)) = 21/31

D) Find E(X).

integral 2 to 4 (x*(3/4)(-x^2 + 6x - 8))dx = 3

E) Find the standard deviation of X.

integral 2 to 4 (x^2(3/4)(-x^2 + 6x - 8))dx E[x^2)-E[x] = sqrt(6.2)= 2.48
 
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  • #2
They will expect you to give the formula of the integrals you mention. For the simple polynomial of this problem, you should be able to do that.
 
  • #3
noreturn2 said:

Homework Statement


f(x) = (3/4)(-x^2 + 6x - 8) for 2 < x < 4 (0 elsewhere)

A) Find F(x)

integral 2 to 4 ((3/4)(-x^2 + 6x - 8))dx

B) Use F(x) to find P(3 < X < 3.5)

integral 3 to 3.5 ((3/4)(-x^2 + 6x - 8))dx

11/32

C) Use F(x) to find P(X > 3.5)

1-( P(3 < X < 3.5)) = 21/31

D) Find E(X).

integral 2 to 4 (x*(3/4)(-x^2 + 6x - 8))dx = 3

E) Find the standard deviation of X.

integral 2 to 4 (x^2(3/4)(-x^2 + 6x - 8))dx E[x^2)-E[x] = sqrt(6.2)= 2.48

(A) ##F(4) = \int_2^4 (3/4) (-x^2 + 6x - 8) \, dx,## but other values of ##F(x)## must be given by something else. What would that be?
(C) is wrong; that is to say, the formula is wrong, but I have not checked the numerical answer.
(E) is partly right, but it looks partly wrong as well; it is hard to say, since what you wrote is almost incomprehensible.
 
  • #4
Thread moved to Calc & Beyond Homework section. Questions involving integrals do not belong in the Precalc section.
 

Related to How Do You Solve These Continuous Probability Problems?

1. What is continuous probability?

Continuous probability is a branch of mathematics that deals with the likelihood of an event occurring within a continuous range of values. It is used to model and analyze real-world situations where outcomes can take on any value within a given range.

2. How is continuous probability different from discrete probability?

Discrete probability deals with events that have a finite or countable number of outcomes, while continuous probability deals with events that have infinite possible outcomes within a range of values. Additionally, discrete probabilities are represented by discrete probability distributions, while continuous probabilities are represented by continuous probability distributions.

3. What is a probability distribution?

A probability distribution is a function that assigns probabilities to the possible outcomes of a random variable. In the case of continuous probability, this function is called a continuous probability distribution and is represented by a curve rather than a table.

4. How is continuous probability calculated?

Continuous probability is calculated by finding the area under the curve of a continuous probability distribution. This can be done using integration techniques such as the definite integral or by using statistical software.

5. What are some real-world applications of continuous probability?

Continuous probability is used in many fields, including physics, engineering, economics, and finance. Some common applications include predicting stock prices, analyzing risk in insurance, and modeling weather patterns.

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