Suppose X has a continuous uniform distribution over the interval [−2,2]
a) Determine the mean, variance, and standard deviation of X
b) Determine the value of a such that P(−a

Respuesta :

Answer:

Mean = 0

Variance = 4/3

Standard Deviation √4/3

a= 0.9

Step-by-step explanation:

If X has a uniform distribution over [a,b] then its Mean is a+b/2 and variance is (b-a)²/12

Here a=  -2 and b= 2

Now finding the mean = a+b/2=-2+2/2= 0

Variance = (b-a)²/12=( 2-(-2))²/12= 4²/12= 16/12= 4/3

Standard Deviation = √Variance= √4/3

b) [tex]\int\limits^a_b f({x}) \, dx[/tex]=  \int\limits^a_a {\frac{1}{a- (-a)} } \, dx

                =1/2a[x]^a_-a= 2a/2a= 1  (applying the limits to the function)

P(−a<X<a) =[tex]\int\limits^a_b {x} \, dx[/tex]=1/2 * 2a= a    (applying the limits to the function)

P(−a<X<a)= 0.9

a= 0.9

In the given question the limits are -a to a . When we apply these in the above instead of [a,b] we get the above answer.

Using the uniform distribution, we have that:

  • The mean is 0.
  • The variance is of 1.25.
  • The standard deviation is of 1.12.

An uniform distribution has two bounds, a and b.

In this problem, interval [−2,2], hence [tex]a = -2, b = 2[/tex].

The mean is:

[tex]E(X) = \frac{a + b}{2}[/tex]

Hence:

[tex]E(X) = \frac{-2 + 2}{2} = 0[/tex]

The variance is:

[tex]V(X) = \frac{(b - a)^2}{12}[/tex]

Hence

[tex]V(X) = \frac{(2 - (-2))^2}{12} = \frac{16}{12} = 1.25[/tex]

The standard deviation is the square root of the variance, hence [tex]\sqrt{1.25} = 1.12[/tex]

A similar problem is given at https://brainly.com/question/14767944