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Given the probability density function f(x) = 1/5 over the interval [4, 9], find the expected value, the
mean, the variance and the standard deviation.
Expected value:
Mean:
Variance:
Standard Deviation:

Given the probability density function fx 15 over the interval 4 9 find the expected value the mean the variance and the standard deviation Expected value Mean class=

Respuesta :

Answer:

Step-by-step explanation:

Assume that f(x) = 0 for x outside the interval [4,9]. We will use the following

[tex]E[X^k] = \int_{4}^{9}x^k f(x) dx[/tex]

[tex]Var(X) = E[X^2}- (E[X])^2[/tex]

Standard deviation = [tex] \sqrt[]{Var(X)}[/tex]

Mean = [tex]E[X][/tex]

Then,

[tex]E[X] = \int_{4}^{9}\frac{1}{5}dx = \frac{9^2-4^2}{2\cdot 5} = \frac{13}{2}[/tex]

[tex]E[X^2] = \int_{4}^{9}\frac{x^2}{5}dx = \frac{9^3-4^3}{3\cdot 5} = \frac{133}{3}[/tex]

Then, [tex]Var(x) = \frac{133}{3}-(\frac{13}{2})^2 = \frac{25}{12}[/tex]

Then the standard deviation is [tex]\frac{5}{2\sqrt[]{3}}[/tex]

Possibilities Density Functions are a set of data measures that can be used to anticipate that a discontinuous value will turn out as the following calculation:

Density function calculated value:

Given function= [tex]\frac{1}{5}[/tex]

interval= [4,9]

Assuming that the given function that is [tex]fx) = 0[/tex] .

For this, the x outside the interval is [4,9].

Equation:

[tex]E[X^k] = \int^{9}_{4} x^k\ f(x) \ dx\\\\[/tex]

[tex]Var(X) = E(X)^2 - (E[X])^2[/tex]

The values are:

Standard deviation [tex]= \sqrt{Var(X)}[/tex]

Mean [tex]= E[X][/tex]

Solving the equation then:

[tex]E[X] =\int^{9}_{4} \frac{1}{5}\ dx[/tex]

         [tex]= \frac{9^2-4^2}{2\cdot 5} \\\\ = \frac{81-16}{10} \\\\ = \frac{65}{10} \\\\=\frac{13}{2} \\\\[/tex]

[tex]E[X^2] =\int^{9}_{4} \frac{x^2}{5}\ dx[/tex]

          [tex]= \frac{9^3-4^3}{3\cdot 5} \\\\= \frac{729-64}{15} \\\\ = \frac{665}{15}\\ \\=\frac{133}{3} \\\\[/tex]

[tex]\to Var(x) = \frac{133}{3} - (\frac{13}{2})^2 = \frac{25}{12}\\\\[/tex]

Therefore the standard deviation value is [tex]\frac{5}{2\sqrt{3}}[/tex]

Find out more about the probability here:

brainly.com/question/11234923

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