Recall that
Var[aX + bY] = a ² Var[X] + 2ab Cov[X, Y] + b ² Var[Y]
Then
Var[3X - 7Y] = 9 Var[X] - 42 Cov[X, Y] + 49 Var[Y]
Now, standard deviation = square root of variance, so
Var[3X - 7Y] = 9×6² - 42×2 + 49×8² = 3376
The general result is easy to prove: by definition,
Var[X] = E[(X - E[X])²] = E[X ²] - E[X]²
Cov[X, Y] = E[(X - E[X]) (Y - E[Y])] = E[XY] - E[X] E[Y]
Then
Var[aX + bY] = E[((aX + bY) - E[aX + bY])²]
… = E[(aX + bY)²] - E[aX + bY]²
… = E[a ² X ² + 2abXY + b ² Y ²] - (a E[X] + b E[Y])²
… = E[a ² X ² + 2abXY + b ² Y ²] - (a ² E[X]² + 2 ab E[X] E[Y] + b ² E[Y]²)
… = a ² E[X ²] + 2ab E[XY] + b ² E[Y ²] - a ² E[X]² - 2 ab E[X] E[Y] - b ² E[Y]²
… = a ² (E[X ²] - E[X]²) + 2ab (E[XY] - E[X] E[Y]) + b ² (E[Y ²] - E[Y]²)
… = a ² Var[X] + 2ab Cov[X, Y] + b ² Var[Y]
Which expressions are not equivalent
? Thanks!
Answer:
D
Step-by-step explanation:
There is no 2x in D answer
Una persona compra borregos, cabras y puercos jabalí. Son 100 animales vivos en total y paga $100 mil pesos. Cada borrego costó $500 pesos, tres cabras cuestan $4000 y cada puerco jabalí $3500.
Si denotamos con la variable xel número de borregos comprados por la persona, con y el número de cabras y con z el número de puercos jabalí, escribe las ecuaciones que representan las relaciones entre x,y,zde acuerdo a la información proporcionada.
Answer:
I'm sorry I just need points
Step-by-step explanation:
(x-14) multiplied by (x+21)=0
Write down all numbers x that satisfy at least one condition.
Answer:
15
Step-by-step explanation:15
what is 75 as a fraction of 125? give your answer in its simplest form.
75 as a fraction of 125 would be 75/125
Now Lets simplify
75/25=3
125/25=5
We get 3/5
We can not reduce 3/5 anymore, so the answer is 3/5
A fraction is a way to describe a part of a whole. such as the fraction ¼ can be described as 0.25. 75 is 3/5 fraction of 125.
What is a Fraction?A fraction is a way to describe a part of a whole. such as the fraction ¼ can be described as 0.25.
Let 75 be x fraction of 125. Therefore, we can write the statement as,
x × 125 = 75
x = 75/125
x = 3 /5
Hence, 75 is 3/5 fraction of 125.
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What percent of 80 is 20? Answer pla
Answer:
25%
Step-by-step explanation:
[tex] \frac{20}{80} = \frac{1}{4} = 0.25 = 25\%[/tex]
URGENT NEED HELP CLICK TO SEE
Answer:
35
Step-by-step explanation:
- x - = +
Therefore :
-5 x - 7 = 35
Multiplying polynomials
(4x+3y)(5x+y)
Answer:
20x^2 +19xy+3y^2
Step-by-step explanation:
See Image below :)
9514 1404 393
Answer:
20x² +19xy +3y²
Step-by-step explanation:
Use the distributive property.
(4x +3y)(5x +y)
= 4x(5x +y) +3y(5x +y)
= 20x² +4xy +15xy +3y²
Collect terms.
= 20x² +19xy +3y²
Find the missing side of each triangle. Round your answers to the nearest tenth if necessary
Answer:
5. 10 cm
6. 12 in
7. 5 mi
8. 13 cm
Step-by-step explanation:
5. 6² + 8² = x²
36 + 64 = x
36 + 64 = 100
√100 = 10
6. 15² - 9² = x²
225 - 81 = 144
√144 = 12
7. 3² + 4² = x²
9 + 16 = x
9 + 16 = 25
√25 = 5
8. 12² + 5² = x²
144 + 25 = x
144 + 25 = 169
√169 = 13
A principal of 3700 is invested at 8.25% interest, compounded annually. How much will the investment be worth after 11 years? Use the calculator provided and round your answer to the nearest dollar.
What is the volume of the rectangular prism?
In how many ways can you answer 15 true/false questions
Answer:
32768
Step-by-step explanation:
Each question has 2 options.
On a true/false test with one question, there are 2¹, or 2 possible answers
On a test with 2 questions, there are 2², or 4 possible answers.
On a test with 3 questions, there are 2³, or 8 possible answers.
So, 2¹⁵ = 32768 possible ways.
8 Mangoes = 30 bananas
5 banana= 2 oranges
15 oranges=? mangoes
Answer:
it would only be 8, unless you need to go down to the decimal point then it would be 8.25
Step-by-step explanation:
it would be 8 because if you need to find how many bananas you have, to do this you would divide 15 by 2 and get 7.5 then you multiply those by 5 to get the number of bananas which would be 37.5, and then if 8 mangos = 30 bananas you only have 8 mangos.
(sorry if this is very jumbled and hard to understand, also getting brainliest would help, thank you)
8x²y²-18
factorise in process
Answer:
u
Step-by-step explanation:
8x²y²-182(4x²y²-9)2((2xy)²-3²)2(2xy-3)(2xy+3)stay safe healthy and happy.PLZZZZZZZZZZZZZZZZZ help
Answer:
true
Step-by-step explanation:
[tex]\frac{x}{2} <20[/tex]
* substitute 30 for x *
[tex]\frac{30}{2} <20\\\frac{30}{2} =15\\[/tex]
we're left with 15 < 20 which is true
The diameter of a dime is 17.91 millimeters, an the height is 1.35 millimeters. What is the volume of a dime? What is the volume of an oblique cylinder formed by stacking 50 dimes? Round your answers to the nearest hundredth.
Answer:
why does no one ever answer these questionsss?? it's always math to, like I'm just trying to pass my quick check, let alone the class. you know how much easier my life would be it's people just answered the questions. I'm gonna run away, to some Scottish Isle and live a quiet life, in a cozy home with the wind outside ruffling through the grass, and the tired tired sea crashing onto the shoreline. I'll only visit my family and friends once a year, but the rest of the time, I'll be there, in the quiet. eventually a young visitor will stumble through my b & b and he'll end up staying there for weeks, for reasons unknown to me. Then, we'll fall in love, to the quiet sound of the ocean outside. And it'll be just us, it'll be our place, our secret. we won't have to deal with the loud, crazy, hectic world. and it will be perfect. but for now I'm stuck trying to pass this math class.
Answer:
The volume of one dime is 340.11 mm3. The volume of 50 dimes is 17.005.32 mm3.
Step-by-step explanation:
Some1 hurry need help
Answer:
B) (-6,9)
Step-by-step explanation:
since it's reflecting on the x-axis, the x is gonna stay the same. the y changes though. opposite of -9 is 9.
hope this helps <3
Answer:
B, (-6, 9)
Step-by-step explanation:
this is because it's like as if it was a mirror, so that is the correct answer
I really need help , someone please help :’( ... ill also make you brainlist.
Answer:
Step-by-step explanation:A)13 miles in feet = 68640 feet
we now need to get the number of cars, we use division to get groups
68640 / 15 = 4576.
we now see there are 4576 cars in the traffic jam.
B)Less, they are longer cars so the divosor would no longer be 15, it would be a higher number. 4576 cars would not be able to fit in a 13 mile stretch if those cars were any longer.
According to the 2000 U.S. Census, 80% of Americans over the age of 25 have earned a high school diploma. Suppose we take a random sample of 120 Americans and record the proportion, p, of individuals in our sample that have a high school diploma.
Answer:
a) The mean is 0.8.
b) The standard deviation is 0.0365.
c) Normal
Step-by-step explanation:
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
80% of Americans over the age of 25 have earned a high school diploma.
This means that [tex]p = 0.8[/tex]
Suppose we take a random sample of 120 Americans
This means that [tex]n = 120[/tex].
Question a:
The mean is:
[tex]\mu = p = 0.8[/tex]
The mean is 0.8.
Question b:
The standard deviation is:
[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.8*0.2}{120}} = 0.0365[/tex]
The standard deviation is 0.0365.
Question c:
By the Central Limit Theorem, approximately normal.
a) The mean is 0.8.
b) The standard deviation is 0.0365.
c) Normal
Here, we have,
we know that,
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean x and standard deviation σ, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean x and standard deviation s = σ/√n .
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean x=p and standard deviation s=√p(1-p)/n
80% of Americans over the age of 25 have earned a high school diploma.
This means that p=0.8
Suppose we take a random sample of 120 Americans
This means that n=120.
Question a:
The mean is:
x=p=0.8
The mean is 0.8.
Question b:
The standard deviation is:
s=0.0365
The standard deviation is 0.0365.
Question c:
By the Central Limit Theorem, approximately normal.
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What is the slope of the line below? If necessary, enter your answer as a
fraction in lowest terms, using the slash ( 1 ) as the fraction bar. Do not enter
your answer as a decimal number or an equation.
The slope of line shown in the graph is 1.
What is Slope?A line's slope is determined by how its y coordinate changes in relation to how its x coordinate changes. y and x are the net changes in the y and x coordinates, respectively. Therefore, it is possible to write the
change in y coordinate with respect to the change in x coordinate as,
m = Δy/Δx where, m is the slope
We have two points from the graph as (8, 8) and (5, 5)
So, the slope of line
Slope = (5- 8)/ (5-8)
slope= (-3)/ (-3)
slope = 1
Also, rise 3 units and run 3 units
Then, slope= Rise/ Run
slope= 3/3
Slope= 1
This, the required slope is 1.
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3100 people attended a football game. If 5% of the people who attended were teenagers, how many teenagers attended the game?
Answer:
155 are teenagers
Step-by-step explanation:
3100 -5%= 2945
2945-3100=155
What is the slope of y<-3/4x-1
Answer:
-3/4
Step-by-step explanation:
In slope-intercept form, the slope is the coefficient of x.
What is the lowest whole number for hypotenuse c when using the formula [tex]\sqrt{a^2+b^2}[/tex] and a = b?
9514 1404 393
Answer:
0
Step-by-step explanation:
If a=b, you are asking for a whole number c such that ...
c = √(a² +a²) = a√2
If 'a' is a whole number, the only whole numbers that satisfy this equation are ...
c = 0 and a = 0.
0 = 0×√2
The lowest whole number c such that c = √(a²+b²) and a=b=whole number is zero.
__
√2 is irrational, so there cannot be two non-zero whole numbers such that c/a=√2.
_____
Additional comment
If you allow 'a' to be irrational, then you can choose any value of 'c' that you like. Whole numbers begin at 0, so 0 is the lowest possible value of 'c'. If you don't like that one, you can choose c=1, which makes a=(√2)/2 ≈ 0.707, an irrational number. The problem statement here puts no restrictions on the values of 'a' and 'b'.
HMP is isosceles triangle with base MP, also NP⊥OM and NM = OP Name the postulate or theorem you can use to prove NHM = OHP
Answer:
HL theorem
Step-by-step explanation:
since NP⊥OM, so, L H is a right angle.
and NM = OP as hypotenuse
HL theorem
NP is perpendicular to OM
<NHO=90°NM =OP given
So the triangles are congruent
sum difference place value of 2 in 4242
Answer:
[tex]\huge\colorbox{violet}{✏﹏ \: ᴀɴsᴡᴇʀ \: }[/tex]
4242
2 = 200 ( 2 is in hundred's place )
4242
2 = 2 ( one's place )
Difference = ?
[tex] = 200 - 2 \\ = 198[/tex]
Sum = ?
[tex] = 200 + 2 \\ = 2[/tex]
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
[tex] \huge\blue{ \mid{ \underline{ \overline{ \tt ꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐ }} \mid}}[/tex]
What is the probability that a person orders sandwich with cheddar cheese
Answer:
16.67%
Step-by-step explanation:
Angle Relationships
Use a calculator to find the approximate value of the expression. Round the answer to two decimal places.
The cosine of the complimentary angle to 38°
a. 0.68
b. -0.16
c. -0.22
d. 0.62
Please select the best answer from the choices provided
Answer:
D. 0.62
Step-by-step explanation:
I calculated it logically
The circumference of the tire of Melvin’s cycle is 2.5m. He took part in a race of 2km. When
he had covered 1.2km, the tire burst. To finish the race, how many more times should the wheel go
round?
Answer:
320
Step-by-step explanation:
Distance to go
2km - 1.2 km = 0.8km = 800m
Revolutions needed
800/2.5 = 320
HELP CAN SOMEONE TELL ME THE ANSWER I CANT GET A BAD GRADE.
Answer:
34.1cm^2
Step-by-step explanation:
Area of triangle = 1/2 x base x height
=1/2 x6.2 x11
=34.1cm^2
what is (20)+(475)? I need it now
The surface area of a rectangular prism is increased by a factor of 16.
By what factor is the volume of the figure increased?
4
8
Оооо
32
64
Answer:
64
Step-by-step explanation:
Answer:
D 64
Step-by-step explanation:
The person above me is correct. Got it right on Edge 2021