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

help I need help with my homework no link please BTW its 9th grade work I need help with number 1 a) I still need help with it​

Answers

Answer:

you need to learn how to "prime factor" numbers....

primes are 2,3,5,7,11,13,17....

they go on forever. ALL whole numbers can be "broken down" into a bunch of primes multiplied together.

take the fractions (top and bottom) and start dividing them bu the smallest prime, and going up until all the numbers multiplied make the original number...

15 = 3 * 5

24= 2 * 12 = 2 * 2 * 6 = 2* 2* * 2 * 6

thus   [tex]\frac{15}{24}[/tex] = [tex]\frac{3 * 5 }{2* 2* 2* 3}[/tex]  now just cancel all the SAME numbers from to to bottom

"pair them up" .... in this case only one of the threes in the bottom "takes out" one of the threes in the top

result [tex]\frac{5}{2*2*2 } = \frac{5}{8}[/tex]

~~~~~~~~~~~~~~~~~~~~

[tex]\frac{21}{35}[/tex]

21= 3 * 7

35= 5* 7

[tex]\frac{3*7}{5*7} = \frac{3}{5}[/tex]

Step-by-step explanation:

Which of the following is a composite number?
A. 1
B. 63
C.O
D. 19

Answers

B. 63

some simple googling would've been able to help you with this. but 0 isn't prime or composite, not sure about 1, 19 is prime, 63 is a definite composite

Ardi and Lei are both travelling by train.
Ardi's train travels 70 km in 35 minutes.
Lei's train travels 585 km.
It leaves at 9:05 and arrives at 13:35.
Work out the difference, in km/h, between the average speed of their trains.

Answers

Answer:

10 kilometer/hour

Step-by-step explanation:

Average speed = Total distance travelled / Total time taken

Ardi:

Total distance travelled = 70 km

Total time taken = 35 minutes = 35/60 hour

Average speed = Total distance travelled / Total time taken

= 70 km ÷ 35/60 hr

= 70 × 60/35

= 4,200/35

= 120 kilometer/hour

Lei:

Total distance travelled = 585 km Total time taken = 9:05 - 13:35 = 4 hours 30 minutes

= 4.5 hours

Average speed = Total distance travelled / Total time taken

= 585 km / 4.5 hours

= 130 kilometer/hour

Difference, in km/h, between the average speed of their trains = Lei's train - Ardi's train

= 130 kilometer/hour - 120 kilometer/hour

= 10 kilometer/hour

Using trial and improvement, find the solution between 5 and 6 for the following equation:

x

2

=

27

Give your answer rounded to 1 DP.

Answers

Answer:

2

Step-by-step explanation:

that is √ 14 which is 27 ×>44.2177

Write the equation of the line (in y = ax+b form) in the
graph below. do not use any spaces when typing your
answer

Answers

Answer:

y=3x-8

Step-by-step explanation:

Aubrey tiene un nuevo estuche de arte con forma de prisma rectangular. El estuche es de 12 cm por 20 cm por 5cm. Lo único dentro del estuche es un nuevo borrador rosa con las dimensiones que se muestran a continuación.

¿Cual es el volumen del estuche que no ocupa por el borrador?

Answers

Respuesta:

720 cm³

Explicación paso a paso:

El volumen de un prisma rectangular viene dado por:

V = largo * ancho * alto

Dimensión de la caja de arte = 12 por 20 por 5

Dimensión del borrador = largo * ancho * alto

Volumen del borrador = 2 por 4 por 0,5

Dimensión del estuche de arte que no contiene borrador:

(12 por 20 por 5) - (2 por 4 por 0,5)

(10 por 16 por 4,5)

Volumen de la caja que no contiene borrador:

10 * 16 * 4,5 = 720 cm³

Three less than 3 times a number, n, is
19 more than twice the number. What
is the number?
А
17
B
19
21
D 22

Answers

The equation is:

3n - 3 = 2n + 19

=> 3n - 2n = 19 + 3

=> n = 22

So, the answer is 22.

pls help and explain answer!!
At a certain point in time, a physicist measures the
speed of a falling object to be 17.6 feet per second.
What is the equivalent speed in miles per hour?
(5280 feet = 1 mile)

Answers

Answer:

0.003 miles per hour

Step-by-step explanation:

Well since 5280 feet gives 1 mile den convert 17.6 feet per sec to miles per hr

which relation is a function?

Answers

the first one because there is only one y value for every x value. you can also use the vertical line test in which you draw vertical lines and make sure the function only passes through it once at each point

The first one because there is only one y value for every x value. The correct option is first.

To determine if a relation is a function, use the vertical line test: If any vertical line intersects the graph of the relation at more than one point, then the relation is not a function. On the other hand, if every vertical line intersects the graph of the relation at most once, then the relation is a function.

In first relation is considered a function, because each input x-value is associated with exactly one output y-value. In other words, for every x-value in the domain of the relation, there can be only one corresponding y-value in the range. Each x-value should not have more than one y-value associated with it.

Therefore, each x-value should not have more than one y-value associated with it. The correct option is first.

Learn more about Function here:

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Solve the equation: 12 - x (x - 3) = (6 - x)(x + 2)

Answers

Answer: the answer is 0

Why 0?:

Step 1: Simplify both sides of the equation

-x * x= -x²

-x * -3= 3x all  together it is ( -x²+3x+12)

for the other side:

-x * x= -x²

6 * x= 6x and x * 2= 2x and 6 * 2= 12

then subtract 6x-4x= 2x so final would be = −x²+4x+12

Step 2: Add x² to both sides.

−x²+3x+12+x²=−x²+4x+12+x² then we are left with 3x+12=4x+12

Step 3: Subtract 4x from both sides.

3x+12−4x=4x+12−4x  --> −x+12=12

Step 4: Subtract 12 from both sides.

−x+12−12=12−12

−x=0

Step 5: Divide both sides by -1 or -x

x=0

can someone help me with this please​

Answers

Answer:

for question B

2A 3C = 70

70-15 = 55/5 = 11.

so each child is 11

while adult 11 + 7.50 = 18.50

Z Is An Even Integar Greater Than 30 And Less Than Or Equal To 34.

Answers

Answer:

32, 34

Step-by-step explanation:

The answer must be grater than 30 so 30 is not an option the integers in the range are 31, 32, 33, and 34 the only even integers in this set are 32, and 34. Hope this helps. :)

x/3 + 8 = 23 . Find the value of x

Answers

Answer:

45

Step-by-step explanation:

x/3 + 8 =23

=> x/3 = 23-8

=> x/3 = 15

=> x = 15 x 3

x = 45

Answer:

x=45

Step-by-step explanation:

To find x isolate the variables by using the properties of equality. First, subtract 8 from both sides, [tex]\frac{x}{3} = 15[/tex]. Then multiply both sides by 3, [tex]x=45[/tex]. Finally, to check you can plug 45 back into the equation, [tex]\frac{45}{3} +8=23[/tex]. Next, solve this equation and get 23=23, since this is a true statement 45 is correct.

Help! Can you please help

Answers

Answer:

14)= 2/3/23 × 1/9/14

= 49/23 × 23/14 = 3/1/2

U CAN USE A CALCULATOR to find the rest......If u have one....

Step-by-step explanation:

11. 1.8

12. 22.6

13. 1.66

14. 3.5

Given the roll of paper towels below how much plastic would be needed to cover the role so it can be sold given the diameter of the role is 10 inches and the height is 13 inches

Answers

Answer:

Amount of plastic need to cover paper role = 565.2 inches

Step-by-step explanation:

Given:

Diameter of paper role = 10 inch

Height of paper role = 13 inch

Find:

Amount of plastic need to cover paper role

Computation:

Radius of paper role = Diameter of paper role / 2

Radius of paper role = 10 / 2

Radius of paper role = 5 inch

Amount of plastic need to cover paper role = Total surface area of cylinder

Amount of plastic need to cover paper role = 2πr(h+r)

Amount of plastic need to cover paper role = 2(3.14)(5)(13+5)

Amount of plastic need to cover paper role = (3.14)(10)(18)

Amount of plastic need to cover paper role = 565.2 inches

what is the answer to the problem

Answers

Answer:

Step-by-step explanation:

29 is 6 more than k

Write it as an mathematical equation!

29 = 6 + k

Then solve for k

K = 29 - 6
K = 23

simplify (-9)×5×6(-3)​

Answers

[tex]\bf \large \hookrightarrow \:( - 9) \: \times \: 5 \: \times \: 6 \: \times \: ( - 3) \\ \\ \bf \Large \hookrightarrow \: \: \: - 45 \: \times \: ( - 18) \\ \\ \bf \Large \hookrightarrow \: \: 810[/tex]

What is the inverse of the function f(x) = x +3?
O h(x) = 5x + 3
O h(x) =
1x-3
Oh(x) = x-3
Oh(x) = x + 3

Answers

I think it’s f^-1(x)=x-3

Explanation:

To find the inverse of a function, just "trade" x and y and solve for the "new" y. The graph of the inverse is the reflection of the original function over the line y=x.

The value of the inverse of the function f(x) = x +3 is,

⇒ h (x) = x - 3

What is mean by Function?

A relation between a set of inputs having one output each is called a function. and an expression, rule, or law that defines a relationship between one variable (the independent variable) and another variable (the dependent variable).

Given that;

Function is,

f (x) = x + 3

Now, We can find the inverse of the function f(x) = x +3 as,

f (x) = x + 3

y = x + 3

x = y - 3

h (x) = x - 3

Thus, The value of the inverse of the function f(x) = x +3 is,

⇒ h (x) = x - 3

Learn more about the function visit:

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2/5x - 1/5y = 98
2/7x - 1/14y = 55
If the ordered pair (x, y) satisfies the system of
equations shown above, what is the value of x?

Answers

Answer:

x = 140

Step-by-step explanation:

Given the equations

[tex]\frac{2}{5}[/tex] x - [tex]\frac{1}{5}[/tex] y = 98 ( multiply through by 5 to clear the fractions )

2x - y = 490 → (1)

[tex]\frac{2}{7}[/tex] x - [tex]\frac{1}{14}[/tex] y = 55 ( multiply through by 14 to clear the fractions )

4x - y = 770 → (2)

Subtract (1) from (2) term by term to eliminate y

2x + 0 = 280

2x = 280 ( divide both sides by 2 )

x = 140

SOMEONE PLEASE HELPPPPPPPPPP

Answers

Answer:

the formula for the volume of a square pyramid is V=a^2*h/3

so if we just put in the data

12^2*10/3

144*10/3

480

so the answer is B

Hope This Helps!!!

Find the product: 3/4 x 2/3. What's the product? 5/7, 6/12, 5/12, 6/7. What is it please help me!!!!

Answers

Answer:

1/2

Step-by-step explanation:

3/4 x 2/3

= 1/2

(a) Determine a cubic polynomial with integer coefficients which has $\sqrt[3]{2} + \sqrt[3]{4}$ as a root.

(b) Prove that $\sqrt[3]{2} + \sqrt[3]{4}$ is irrational.

Answers

Answer:

(a) [tex]x\³ - 6x - 6[/tex]

(b) Proved

Step-by-step explanation:

Given

[tex]r = $\sqrt[3]{2} + \sqrt[3]{4}$[/tex] --- the root

Solving (a): The polynomial

A cubic function is represented as:

[tex]f = (a + b)^3[/tex]

Expand

[tex]f = a^3 + 3a^2b + 3ab^2 + b^3[/tex]

Rewrite as:

[tex]f = a^3 + 3ab(a + b) + b^3[/tex]

The root is represented as:

[tex]r=a+b[/tex]

By comparison:

[tex]a = $\sqrt[3]{2}[/tex]

[tex]b = \sqrt[3]{4}$[/tex]

So, we have:

[tex]f = ($\sqrt[3]{2})^3 + 3*$\sqrt[3]{2}*\sqrt[3]{4}$*($\sqrt[3]{2} + \sqrt[3]{4}$) + (\sqrt[3]{4}$)^3[/tex]

Expand

[tex]f = 2 + 3*$\sqrt[3]{2*4}*($\sqrt[3]{2} + \sqrt[3]{4}$) + 4[/tex]

[tex]f = 2 + 3*$\sqrt[3]{8}*($\sqrt[3]{2} + \sqrt[3]{4}$) + 4[/tex]

[tex]f = 2 + 3*2*($\sqrt[3]{2} + \sqrt[3]{4}$) + 4[/tex]

[tex]f = 2 + 6($\sqrt[3]{2} + \sqrt[3]{4}$) + 4[/tex]

Evaluate like terms

[tex]f = 6 + 6($\sqrt[3]{2} + \sqrt[3]{4}$)[/tex]

Recall that: [tex]r = $\sqrt[3]{2} + \sqrt[3]{4}$[/tex]

So, we have:

[tex]f = 6 + 6r[/tex]

Equate to 0

[tex]f - 6 - 6r = 0[/tex]

Rewrite as:

[tex]f - 6r - 6 = 0[/tex]

Express as a cubic function

[tex]x^3 - 6x - 6 = 0[/tex]

Hence, the cubic polynomial is:

[tex]f(x) = x^3 - 6x - 6[/tex]

Solving (b): Prove that r is irrational

The constant term of [tex]x^3 - 6x - 6 = 0[/tex] is -6

The divisors of -6 are: -6,-3,-2,-1,1,2,3,6

Calculate f(x) for each of the above values to calculate the remainder when f(x) is divided by any of the above values

[tex]f(-6) = (-6)^3 - 6*-6 - 6 = -186[/tex]

[tex]f(-3) = (-3)^3 - 6*-3 - 6 = -15[/tex]

[tex]f(-2) = (-2)^3 - 6*-2 - 6 = -2[/tex]

[tex]f(-1) = (-1)^3 - 6*-1 - 6 = -1[/tex]

[tex]f(1) = (1)^3 - 6*1 - 6 = -11[/tex]

[tex]f(2) = (2)^3 - 6*2 - 6 = -10[/tex]

[tex]f(3) = (3)^3 - 6*3 - 6 = 3[/tex]

[tex]f(6) = (6)^3 - 6*6 - 6 = 174[/tex]

For r to be rational;

The divisors of -6 must divide f(x) without remainder

i.e. Any of the above values  must equal 0

Since none equals 0, then r is irrational

Eva created a coffee blend for her restaurant by mixing Kenya and French Roast coffee beans. The Kenya beans cost $15 per pound and the French Roast costs $8 per pound. She bought a total of 10 pounds of coffee for a total of $97.50. Please help ASAP!!!!

Answers

Answer:

what is the question you are only telling us the fact

Step-by-step explanation:

How to find the frequency in a histogram

Answers

Answer:Para preparar la tabla de frecuencia para un histograma, es necesario primero establecer el número de intervalos que se desea tener.

Luego, se debe determinar el ancho común de los intervalos (interval width). Para esto, se calcula la diferencia del dato mayor y el dato menor, y se divide entre el número de intervalos deseados. Este resultado se redondea al entero mayor más cercano.

Por ejemplo, si se desea tener 10 intervalos y encontramos que el dato mayor es 35 y el menor es 12,

Step-by-step explanation:

You buy a 1:10000 scale model of the One World Trade Center during a trip to New York City. The height of the model is 5.41 centimeters. Find the actual height x (in meters) of the One World Trade Center.

Answers

Answer:

541m

Step-by-step explanation:

The scale given 1 represents the height of the model and 10000 represents the actual height,place the 5.41 in line with the one and an unknown letter in line with the 10000 inorder to calculate the actual height

1:10000

5.41:x

cross multiply and solve for x,which will be 54100cm

but since the answer has to be in meters convert the 54100cm to a meter by dividing it by 100..

What is the midpoint of the segment shown below?

Answers

Step-by-step explanation:

simply take the average of the x and y coordinates

A farm grew 19.8 tons of wheat in 2013. The farm's wheat output increased by 9.8% from 2013 to 2014 and by 5.1% from 2014 to 2015. Which expression represents a for estimating the total output of wheat, in tons, in 2015?

A. 20 + 10 + 5
B. 20(10)(5)
C. 20 + 1.1 + 1.05
D. 20(1.1)(1.05)

Answers

Answer: Choice D

Explanation:

The increase of 9.8% rounds to 10% when rounding to the nearest ten

An increase of 10% would use the multiplier 1.1

Think of it like saying 1 + 0.10 = 100% + 10%

Similarly, the 5.1% rounds to 5% and an increase of this amount will use the multiplier 1.05

So if we started with 20 items, then 20(1.1)(1.05) is the expression that estimates an increase of 10% followed by an increase of 5%. The order doesn't matter (so you could increase by 5% first, then 10% later).

Can someone help me with this math homework please!

Answers

Answer:

x = 12.5

Step-by-step explanation:

Explanation in progress ;-)

(17)^ 3 *(289)^ -6 =(17)^ 2m - 1​

Answers

Answer:

m = -4

Step-by-step explanation:

The given expression is :

[tex](17)^{3}\cdot(289)^{-6}=(17)^{2m-1}[/tex]

We need to find the value of m

We know that, 17² = 289

So,

[tex](17)^{3}\cdot(17^2)^{-6}=(17)^{2m-1}\\\\(17)^{3}\cdot(17)^{-12}=(17)^{2m-1}[/tex]

Also,[tex]x^ax^b=x^{a+b}[/tex]

So,

[tex]17^{3-12}=17^{2m-1}\\\\17^{-9}=17^{2m-1}\\\\\implies -9=2m-1\\\\-9+1=2m\\\\-8=2m\\\\m=-4[/tex]

So, the value of m is equal to -4.

Rewrite the expression as a simplified expression containing one term.

Answers

Answer:

-(cos α)/(sin α)

= -cot α

Step-by-step explanation:

use trigonometric identities

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