How do you simplify or evaluate expressions?

Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviat

drek231 [11]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

Step-by-step explanation:

For this case we have the following probability distribution given:

X 0 1 2 3 4 5

P(X) 0.031 0.156 0.313 0.313 0.156 0.031

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

We can verify that:

$\sum_{i=1}^n P(X_i) = 1$

And $P(X_i) \geq 0, \forall x_i$

So then we have a probability distribution

We can calculate the expected value with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 0*0.031 +1*0.156+ 2*0.313+3*0.313+ 4*0.156+ 5*0.031 = 2.5$

We can find the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 0^2*0.031 +1^2*0.156+ 2^2*0.313+3^2*0.313+ 4^2*0.156+ 5^2*0.031 =7.496$

And we can calculate the variance with this formula:

$Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246$

And the deviation is:

$Sd(X) = \sqrt{1.246}= 1.116$

6 0

3 years ago

I need help answering this question, Asap

Natasha2012 [34]

Answer:

(-65)/17

Step-by-step explanation:

Evaluate 3/(x - 2) - sqrt(x - 3) where x = 19:

3/(x - 2) - sqrt(x - 3) = 3/(19 - 2) - sqrt(19 - 3)

19 - 3 = 16:

3/(19 - 2) - sqrt(16)

19 - 2 = 17:

3/17 - sqrt(16)

sqrt(16) = sqrt(2^4) = 2^2:

3/17 - 2^2

2^2 = 4:

3/17 - 4

Put 3/17 - 4 over the common denominator 17. 3/17 - 4 = 3/17 + (17 (-4))/17:

3/17 - (4×17)/17

17 (-4) = -68:

3/17 + (-68)/17

3/17 - 68/17 = (3 - 68)/17:

(3 - 68)/17

3 - 68 = -65:

Answer: (-65)/17

4 0

3 years ago

Read 2 more answers

What is the answer to 2a+3=9a-4

bixtya [17]

Solve for a by simplifying both sides of the equation, then isolating the variable.
a = 1

5 0

3 years ago

Read 2 more answers

What the square root

MrRissso [65]

Answer:

-7.07106

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Find the value of x.<br> 31.7, 42.8, 26.4, x, mean 35

Troyanec [42]

Answer:

x = 39.1

Step-by-step explanation:

mean = average off all the numbers =

sum of the numbers / amount of numbers.

35 = sum of the #'s / # of #'s

35 = 100.9 + x / 4

35 × 4 = 100.9 + x / 4 × 4

140 = 100.9 + x

140 – 100.9 = 100.9 + x – 100.9

39.1 = x

x = 39.1

6 0

3 years ago