Suppose that X1 and X2 are independent random variables each with a mean μ and a variance σ^2. Compute the mean and variance of Y = 3X1 + X2.

Answers

Answer 1

Mean:

E[Y] = E[3X₁ + X₂]

E[Y] = 3 E[X₁] + E[X₂]

E[Y] = 3µ + µ

E[Y] = 4µ

Variance:

Var[Y] = Var[3X₁ + X₂]

Var[Y] = 3² Var[X₁] + 2 Covar[X₁, X₂] + 1² Var[X₂]

(the covariance is 0 since X₁ and X₂ are independent)

Var[Y] = 9 Var[X₁] + Var[X₂]

Var[Y] = 9σ² + σ²

Var[Y] = 10σ²


Related Questions

What is the slope of the line represented by the equation y=
iy=-x+ .
0

○ 4
0를
O
0를

Answers

Answer:

-1/2

Step-by-step explanation:

Equation is put in slope intercept form:

y = mx + b

Where m = slope

-1/2 takes the place of m meaning that the slope is -1/2

Using linear function concepts, it is found that the slope of the line is of:

[tex]-\frac{1}{2}[/tex]

What is a linear function?

A linear function is modeled by:

[tex]y = mx + b[/tex]

In which:

m is the slope, which is the rate of change, that is, by how much y changes when x changes by 1.b is the y-intercept, which is the value of y when x = 0.

In this problem, the equation is:

[tex]y = -\frac{1}{2}x + \frac{1}[4}[/tex]

Thus the slope is of [tex]m = -\frac{1}{2}[/tex].

More can be learned about linear function concepts at https://brainly.com/question/24808124

(100 points)

1.One of the addends of 17,300 is 11,210. What is the other addend?

a. What are they asking for? __________________

b. identify all the necessary numbers. __________________

c. write the equation or problem in numeric form. ______________

d. solve the math. ______________________________

e.write the answer. ________________________________


2. If one of the factors of 954 is 318 , what is the other factor?

a. What are they asking for? __________________

b. identify all the necessary numbers. __________________

c. write the equation or problem in numeric form. ______________

d. solve the math. ______________________________

e.write the answer. ________________________________


3. HEector bought seven bokes of fruit. Each boc contained 24 fruit. How much fruit did Hector buy?

a. What are they asking for? __________________

b. identify all the necessary numbers. __________________

c. write the equation or problem in numeric form. ______________

d. solve the math. ______________________________

e.write the answer. ________________________________

Answers

Answer:

1a. The other addend of 17,300

1b. 17,300 and 11,210

1c. 17,300-11,210

1d. 17,300-11,210= 6090

1e. 6090

2a. The other factor of 954

2b. 954 and 318

2c. 954-318

2d. 954-318= 636

2e. 636

3a. The total amount of fruit Hector bought.

3b. 7 and 24

3c. 7 x 24

3d. 7 x 24 = 168

3e. 168 fruits

At a certain store, a CD costs $12. If the cost of CDs were graphed as the output, compared to the number of
CDs purchased as input, which of the following would not be true of the graph?
A. The set of points would all lie on the same line.
B. The set of points would include the origin.
C. The set of points would rise from left to right.
D. The set of points would not graph a function.
Please select the best answer from the choices provided
A
B
C
D

Answers

Answer: The best and most correct answer among the choices provided by the question is A. The set of points would all lie on the same line.    

     

Which algebic expression is “ ten less than a number divided by twelve “

Answers

You can use any variable for “number”. I’m gonna use “x”.

The answer is: (x-10)/12

Which of the following is an even function?

Answers

The one you put is actually correct

Solve for X.

-8(1 - 4x) = -104

Please show work

Answers

Answer:

-3

Step-by-step explanation:

-8(1-4x)=-104

1-4x=-104/-8

1-4x=13

4x=1-13

4x=-12

x=-12/4

x=-3

Find the circumference of a circle with diameter,
d
= 8cm.
Give your answer rounded to 3 SF.

Answers

Answer:

25.1 cm

Step-by-step explanation:

c = πd

c = π*8

c = 25.1327412287

Rounded

c = 25.1 cm

The force "F" applied on a spring and its extension "x" is given by the relation F = - k*x where "k" is the constant of proportionality.

Find "k" if a force of 10 Newtons produces an extension of 5 cm.

A. - 50 N/cm
B. 0.5 N/cm
C. - 20 N/cm
D. - 2 N/cm

HELP

Answers

Answer:

F = -k × X

10 Newtons = -k × 5 cm -k = 10 N/5 cm

-k = 2N/cm

k = -2N/cm

The value of spring constant "k" is -2 N/cm. Thus, the correct answer is option D.

To find the constant of proportionality "k," we can rearrange the formula:

F = -k x x

Since we are given that a force of 10 Newtons produces an extension of 5 cm, we can substitute these values into the equation:

10 N = -k x 5 cm

To solve for "k," we divide both sides of the equation by 5 cm:

k = -10 N / 5 cm

Simplifying the expression:

k = -2 N/cm

Therefore, the value of "k" is -2 N/cm. Thus, the correct answer is option D.

To know more about an expression follow

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Encontrar la magnitud de la velocidad angular de un disco de 0.75 rev/así como la magnitud de su desplazamiento angular Si su movimiento duró 180 segundos

Answers

Answer:

La magnitud de la velocidad angular es 0.026 rad/s y la magnitud del desplazamiento angular es 4.71 rad.

Step-by-step explanation:

Podemos encontrar la magnitud de la velocidad angular (ω) del disco con la siguiente ecuación:

[tex] \omega = \frac{\theta}{t} [/tex]

En donde:

θ: es el desplazamiento angular = 0.75 rev

t: es el tiempo = 180 s

Primero debemos cambiar las unidades del desplazamiento angular de revoluciones a radianes:

[tex] \theta = 0.75 rev*\frac{2\pi rad}{1 rev} = 4.71 rad [/tex]

Entonces, la velocidad angular es:

[tex] \omega = \frac{4.71 rad}{180 s} = 0.026 rad/s [/tex]

Por lo tanto, la magnitud de la velocidad angular es 0.026 rad/s y la magnitud del desplazamiento angular es 4.71 rad.

Espero que te sea de utilidad!        

Consider the equation: x^2 - 4x + 4 = 2x

Rewrite the equation by completing the square:
Your equation should look like (x+a)^2 = b or (x-c)^2 = d
______

What are the solutions to the equation? (1 right answer!)

Answers

Answer:

(x+3)^2=5

Step-by-step explanation:

x^2-4x+4=2x

x^2-6x+4=0

x^2-6x+9-5=0

(x-3)^2-5=0

(x-3)^2=5

A stereo was originally priced at 75.50. it was marked down 24%. a store had a big sale of 60% off the lowest marked price. what was the final price of the stereo

Answers

Answer:

We can calculate the price with both  sales by multiplying the 75.5 units of money by both percentages (to multiply them, we divide them by 100 first):

75.5 * 0.24 * 0.6 [tex]\approx.[/tex] 10.8

find the value of x pls show work

Answers

Answer:

x = 55°

Step-by-step explanation:

120° = x° + 65° (alternate interior angles are congruent)

Subtract 65 from each side

120° - 65° = x° + 65° - 65°

55° = x

Therefore,

x = 55°

find the sum of the first 20 terms of the arithmetic sequence 4, -4, -12, -20​

Answers

Answer:

The sum of the first 20 terms is -1440.

Step-by-step explanation:

We want to find the sum of the first 20 terms of the arithmetic sequence:

4, -4, -12, -20...

The sum of an arithmetic sequence is given by:

[tex]\displaystyle S=\frac{k}{2}(a+x_k)[/tex]

Where k is the number of terms, a is the initial term, and x_k is the last term.

Since we want to find the sum of the first 20 terms, k = 20.

Our initial term a is 4.

Our last term is also the 20th term as we want the sum of the first 20 terms.

To find the 20th term, we can write an explicit formula for our sequence. The explicit formula for an arithmetic sequence is given by:

[tex]x_n=a+d(n-1)[/tex]

Where a is the initial term, d is the common difference, and n is the nth term.

Our initial term is 4. From the sequence, we can see that our common difference is -8 since each subsequent term is eight less than the previous term. Therefore:

[tex]x_n=4-8(n-1)[/tex]

Then the last or 20th term is:

[tex]x_{20}=4-8(20-1)=4-8(19)=-148[/tex]

Therefore, the sum of the first 20 terms are:

[tex]\displaystyle\begin{aligned} S_{20}&=\frac{(20)}{2}\left((4)+(-148))\\&=10(-144) \\&= -1440\end{aligned}[/tex]

Answer:

- 1440

Step-by-step explanation:

First-term is 4 and we subtract 8 to get the next term so the general term is

a(n) = 4 - 8(n -1)

The sum of the sequence is the average of the first and last terms multiplied by the number of terms: (a1 + an)/2 * n

We need the 20th term: a20 = 4 - 8(20–1) = 12 - 160 = - 148

The sum is (4 - 148)/2 * 20 = 10*(-144) = - 1440

If A and B are independent events, P(A and B) =

Answers

Answer:

If A and B are independent events, then the events A and B' are also independent. Proof: The events A and B are independent, so, P(A ∩ B) = P(A) P(B). From the Venn diagram, we see that the events A ∩ B and A ∩ B' are mutually exclusive and together they form the event A.

Answer:

Step-by-step explanation:

Given A and B are independent events, P(A and B) = P(A)*P(B)

Using the approximation of 5 miles = 8 km

How many km is 12.5 miles?

Answers

20 km
12.5 miles = (12.5*8)/5 = 20 km

Answer:

20km is in 12.5miles

Step-by-step explanation:

5miles= 8km

12.5miles=xkm

12.5÷5miles=2.5miles

2.5miles/km

2.5×8km=20km

3 + 5 . (-3)=
5 . ( - 6 + 2 ) - 4=
- 5 + 8 . 2 + 1=
4/6 + 13/6 - 5/6=
2 . 8 - 5 . (3 - 4)=
7/3 . 5/2=

Answers

Step-by-step explanation:

PEMDAS rule

3 -15 = -12

-20 - 4 = -24

-5 + 16 + 1 = 12

= 12/6 which = 2

15 + 5 = 20

35/6 = 5 5/6

PLEASE HELP!10 POINTS
find the maximum value of c=x+3y subject to the following constraints:
9x+2y≥35
x+3y≥14
x≥0
y≥0

Answers

Hello,

14

just see my picture

What is the value of tan 0 in the unit circle below?

Answers

Answer:

1 / sqrt(3)

Step-by-step explanation:

tan(o) = sin(o) / cos(o)

sin(o) is the vertical distance from the x-axis. and that is in this basic circle the y-coordinate of the point.

cos(o) is the horizontal distance from the y-axis. that is the x-coordinate of the point.

so,

tan(o) = (1/2) / (sqrt(3)/2) = (2×1) / (2×sqrt(3)) = 1/sqrt(3)

Suppose that a department contains 10 men and 12 women. How many ways are there to form a committee with six members if it must have the same number of men and women

Answers

Answer:

The number of ways is 26,400 ways

Step-by-step explanation:

Given;

total number of men, M = 10

total number of women, W = 12

number of committees to be formed = 6

If there must be equal gender, then it must consist of 3 men and 3 women.

[tex]The \ number \ of \ ways = 10C_3 \times 12C_3\\\\The \ number \ of \ ways =\frac{10!}{3!7!} \times \frac{12!}{3!9!} \\\\T he \ number \ of \ ways = 120 \times 220 = 26,400 \ ways[/tex]

Therefore, the number of ways is 26,400 ways

Solve the inequality and express your answer in interval notation
x^2 - 12x + 3 <0

Answers

Answer:

x is ( -∞, 6-√(33) ) U ( 6+√(33) , -∞ )

Step-by-step explanation:

I have attached the explanation on the image above, hopefully this help

If a flexible air-filled container has a volume of 40 cu ft on the surface, what would the volume be at 99 feet in sea water

Answers

Answer:

50 cu ft

Step-by-step explanation:

The volume of flexible air filled container at 99 feet in sea water is 10 cu.ft.

What is Boyle's law?

Boyle's Law states that If the temperature is constant, the volume of a  gas is inversely proportional to the absolute pressure.

V 1/V2 =P2/P1

V2 = P1 x V1 /P2

Substitute 60 psi for P2, 14.7 psi for P1 and 40cu.ft for V1, we get the volume V2

V2 = 40 x 14.7 / 60

V2 = 9.8 cu.ft

Volume is approximately 10 cu.ft.

Thus, the volume of flexible air filled container at 99 feet in sea water is 10 cu.ft.

Learn more about Boyles law.

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A sequence has a common ratio of Three-halves and f(5) = 81. Which explicit formula represents the sequence?

Answers

Answer:

[tex]f(n) = \frac{32}{3}(\frac{3}{2})^n[/tex]

Step-by-step explanation:

Given

[tex]r = \frac{3}{2}[/tex]

[tex]f(5) = 81[/tex]

Required

The geometric sequence

A geometric sequence is represented as:

[tex]f(n) = ar^{n-1}[/tex]

Replace n with 5

[tex]f(5) = ar^{5-1}[/tex]

[tex]f(5) = ar^4[/tex]

Substitute values for f(5) and r

[tex]81 = a* (\frac{3}{2})^4[/tex]

Open bracket

[tex]81 = a* \frac{81}{16}[/tex]

Make a the subject

[tex]a = \frac{81 * 16}{81}[/tex]

[tex]a = 16[/tex]

So, the explicit function is:

[tex]f(n) = ar^{n-1}[/tex]

[tex]f(n) = 16 * (\frac{3}{2})^{n-1}[/tex]

Split

[tex]f(n) = 16 * (\frac{3}{2})^n \div (\frac{3}{2})[/tex]

Convert to multiplication

[tex]f(n) = 16 * (\frac{3}{2})^n * \frac{2}{3}[/tex]

[tex]f(n) = \frac{32}{3}(\frac{3}{2})^n[/tex]

Answer:

f(x) = 16*(3/2)^(x-1)

Step-by-step explanation:

right on edge

PLEASE HELP ITS EASY BUT LIKE yh

Answers

Answer:

40  I told u

Step-by-step explanation:

right angles are 90 degrees

Answer :

x +25 +25 =90 degrees

x +50 =90 degrees

x = 90 -50

x = 40 degrees

PLZZ HELPPPPPP I NEED TO FINISH THIS IN 8 MINS

Answers

Answer:

$29.69

Step-by-step explanation:

23.52 * 1.1 = $25.872 so this is the marked up price. ----- (1.1 = 110%)

25.872 * 0.1475 = $3.81612  is the sales tax.

Total is 25.872 + 3.81612  ~ $29.69

What is the solution of 5/2x-7=3/4x+14

Answers

Answer:

D. x = 12

Step-by-step explanation:

if you plug 12 in

the solutoon says 23 = 23 which is correct

Answer:D 12

Step-by-step explanation:

I took the test

SOMEONE HELP ASAP PLEASEEEEE!!!!!

Answers

Answer:

the answer is 35% probability

your welcome

could someone help me with this ASAP?

Answers

Answer:

just draw a circle that connects all of the 10's on the graph.

a circle is NOT a function

Step-by-step explanation:

Identify the parent function.

Answers

linear lines, i’m pretty sure

Answer:

Reciprocal

Step-by-step explanation:

PLEASE HELP!!!!!!!!!





A car manufacturer does performance tests on its cars. During one test, a car starts from rest, and accelerates at a constant rate for 20 seconds. Another car starts from rest three seconds later, and accelerates at a faster constant rate. The equation that models the distance (d) in metres the first car travel travels is: d=1.16t^2, where t is time, in seconds, after the car starts. The equation for the second car is: d= 1.74(t-3)^2


a. In the context, what is a suitable domain for the graph of this system?


b. At what time will both cars have driven the same distance?


c. How far will they have driven at this time?

Answers

Answer:

15.66

Step-by-step explanation:

HELPPP IM ALMOST DONE WITH THIS CLASS

Answers

Answer: Choice D)  y = cos(2x)

Explanation:

Normally, cosine has a period of 2pi. This means that the curve repeats itself every 2pi units. However, this graph has a period of pi.

We can see this by noting that the distance from one peak such as x = 0 to another adjacent peak x = pi is exactly pi units across.

Since T = pi is the period, we then know that

B = (2pi)/T

B = (2pi)/(pi)

B = 2

Then recall that the general template is y = Acos(B(x-C))+D

In this case, A = 1, C = 0 and D = 0. So all of this leads to y = cos(2x)

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