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]
A box contains 3 plain pencils and 9 pens. A second box contains 9 color pencils and I crayon. One item from each box is chosen at random. What is the
probability that a pen from the first box and a crayon from the second box are selected?
Write your answer as a fraction in simplest form.
Find the volume of the cone. Round your answer to the nearest hundredth
Answer:
[tex]V=8042.47\ cm^3[/tex]
Step-by-step explanation:
Given that,
The radius of the cone, r = 16 cm
The height of the cone, h = 30 cm
The slant height of the cone, l = 34 cm
We need to find the volume of the cone. The formula for the volume of a cone is given by :
[tex]V=\dfrac{1}{3}\pi r^2 h[/tex]
Put all the values,
[tex]V=\dfrac{1}{3}\times \pi \times (16)^2 \times 30\\\\V=8042.47\ cm^3[/tex]
So, the volume of the cone is equal to [tex]8042.47\ cm^3[/tex].
Select each equation that the number 10^3 makes true.
6.01 x
= 601
O 0.305 x
= 305
0.54 x
= 540
O 0.097 x
970
0.97 x
= 97
All of the equations which the number 10³ makes true include the following:
B. 0.305 × __ = 305
C. 0.54 × __ = 540
How to determine the true equations?In this exercise, you are required to determine the equations which the number 10³ makes true. This ultimately implies that, we would substitute the number 10³ into each of the given equations as follows;
6.01 × 10³ = 601
By expanding the exponent, we have the following equation:
6.01 × 1,000 = 601
6010 = 601 (False).
0.305 × 10³ = 305
By expanding the exponent, we have the following equation:
0.305 × 1,000 = 305
305 = 305 (True).
0.54 × 10³ = 540
By expanding the exponent, we have the following equation:
0.54 × 1,000 = 540
540 = 540 (True).
0.097 × 10³ = 970
By expanding the exponent, we have the following equation:
0.097 × 1,000 = 970
97 = 970 (False).
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Find f(5): x2 + x + 5
Answer:
20
Step-by-step explanation:
please help me i need it
Select the answer with the correct number of significant figures for each calculation. 31.580 + 4.26 = 35.8 35.84 35.840
Answer:
35.84
Step-by-step explanation:
(101,2,108,104,102,107,109,102) what is the best measure of center for this data set
Answer:
q02 because it is showed the most times
Write in standard form 0.0003251
Answer:
Step-by-step explanation:
The answer is 3.2510 x 10^-4
Please help me guys also i would like the answer to be type out instead of a pic of it alot more easier for me thanks
Answer:I think it’s 10718.571428571 but rounded to a tenth it’s 10724.6
Step-by-step explanation: 10,150+10211+10424+10769+10844+11155+11477 divided by 7 equals 10718.571428571 or 10724.6.
Determine whether Rolle's Theorem applies to the following function on the given interval. If so, find the point(s) that are guaranteed to exist by Rolle's Theorem.
g(x) = x3 + x2-x-1:(-1,1)
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
O A. Rolle's Theorem applies and the point(s) guaranteed to exist is/are x =
(Type an exact answer, using radicals as needed. Use a comma to separate answers as needed.)
B. Rolle's Theorem does not apply.
Answer:
I have attached the answers
4.
At Juicy Deals grocery store, 4 oranges
cost $7.00. You can buy 7 oranges
for $12.50.
Is the relationship between the number of
oranges and their price proportional?
Explained step by step please
Answer:
True
Step-by-step explanation:
Let's call
x: number of oranges
y: price
The relationship between x and y is proportional if they fulfill the following condition.
y / x = k
where,
k is a proportionality constant
Then,
6 / 4 = 15 / 10 = 1.5
Since x and y fulfill the condition, they have a relationship of proportionality.
There are 14 math teachers and 26 science teachers at school today. What is the ratio of math teachers to math and science teachers at school?
Answer:
SEE EXPLANATION
Step-by-step explanation:
Add all amount of teachers together
14+26 = 40
14:40
Simplified: 7/20 or 7:20
Ratios are just like fractions and can usually be put in this format
Answer:
7:20
Step-by-step explanation:
14+26=40
40 equals the total amount of teachers. Since we want to do the ratio of math teachers to the total of all teachers, we had to find 40.
You get 14:20 though if you want to simplify, find to common denominator (2) and dived both sides by it.
14/2 = 7
40/2 = 20
= 7:20
What is the equation of the least squares regression line for the data set?
The equation of the least squares regression line for the data set is (b) ŷ = -2.984x + 112.38
How to determine the equation of the least squares regression line for the data setFrom the question, we have the following parameters that can be used in our computation:
Volunteer 15 11 22 35 18 41 27 18
Trees 77 99 4 11 44 14 2 90
Using a graphing calculator, we have the following calculation summary
Sum of X = 187Sum of Y = 341Mean X = 23.375Mean Y = 42.625Sum of squares (SSX) = 741.875Sum of products (SP) = -2213.875The regression equation is represented as
ŷ = bX + a
Where
b = SP/SSX = -2213.88/741.88 = -2.98416
a = MY - bMX = 42.63 - (-2.98*23.38) = 112.37978
So, we have
ŷ = -2.98416X + 112.37978
Approximate
ŷ = -2.984x + 112.38
Hence, the equation is ŷ = -2.984x + 112.38
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Write an equation of a line that is perpendicular to 6x - 3y = -6 and passes
through the point (-12, 14).
I'm sorry but I didn't get that
Which expression is equivalent to 4y^6+8y^4/2y^2, if y does not equal 0?
A. 2y^3+4y^2
B. 2y^4+4y^2
C. 1/2y^3+4y^2
D. 1/2y^4+4y^2
9514 1404 393
Answer:
The correct answer choice is marked
Step-by-step explanation:
The distributive property can be used here.
[tex]\displaystyle \frac{4y^6+8y^4}{2y^2}=\frac{4y^6}{2y^2}+\frac{8y^4}{2y^2}=2y^{6-2}+4y^{4-2}=\boxed{2y^4+4y^2}[/tex]
A company is producing picture frames as well as the glass for the front of the frames. The amount of wood required
for the frame is represented by the function W/(x), and the amount of glass is represented by the function G(x). The
frames have lengths represented by the function f(x) and widths represented by g(x).
X
2
3
4
5
W(x)=2[(f+g)(x)]
14
24
34
44
G(x) = (f-g)(x)
6
27
60
105
Which statement describes the combined functions W(x) and G(x)?
O The amount of glass required has a constant rate of change, but the amount of wood does not.
O The amount of wood required has a constant rate of change, but the amount of glass does not.
O Both the amount of wood required and the amount of glass required have a constant rate of change.
ONeither the amount of wood required nor the amount of glass required has a constant rate of change.
Answer:The combined functions W(x) and G(x) represent the amount of wood and glass required to produce a picture frame. Based on the information provided,
W(x)= 2[(f+g)(x)] and G(x) = (f-g)(x)
By looking at the values of the given table, it can be observed that the rate of change in the amount of glass required (G(x)) is not constant, it increases as x increases.
On the other hand, the rate of change in the amount of wood required (W(x)) is not constant as well, it increases as x increases too.
It's not mentioned any information about constant rate of change for f and g.
Therefore, the correct statement that describes the combined functions W(x) and G(x) is: "Neither the amount of wood required nor the amount of glass required has a constant rate of change."
It's important to mention that the problem provided does not have a unique solution, because the values for f and g are not defined so it's not possible to infer their behaviour over time.
It is only possible to infer the behaviour of the functions W(x) and G(x) given the information provided, and it is clear that the rate of change for both functions does not remain constant, but it increases as x increases.
Step-by-step explanation:
when a positive integer was multiplied by each of its digits, the product was 1995. Find the original number.
Answer:
57
Step-by-step explanation:
You want a positive number that gives a product of 1995 when it is multiplied by each of its digits.
NumberThe prime factors of 1995 are 3, 5, 7, 19. The product of 3 and 19 gives 57, so multiplying 57 by 5 and 7 will result in the product 1995.
The original number is 57.
<95141404393>
A pilot must log at least 1100 hours to fly an aircraft. Jabari logged 300 hours. How many more hours must he log to qualify
Answer: 800 more hours is required to fly an aircraft
Step-by-step explanation:
Ricky went to sleep at 9:45 pm and woke up at 6:30 the next morning. For how long did he sleep?
Answer:
8 hours and 45 minutes.
Step-by-step explanation:
please HELPPPPP according to the Marcus trail mix recipe 2 cups of dry food should be used for every 3 1/2 cups of salted nuts at this rate how many cups of nuts should be used for 3 cups are dried fruit is used?
You are making a sandwich. You need lettuce, tomato, and two slices of bread to make the sandwich....
L = lettuce. T = Tomato. B = Bread. S = Sandwich
Vegetables ( Lettuce and tomato) are $2 a piece. Bread is $1 a slice.
The cost of a sandwich can be represented by the equation: {L+T+B+B = S.}
1.) Write another equation you could use to show the cost of a sandwich. (hint: add then multiply)
2.) Figure out the cost of a sandwich (Solve for S).
Answer:
[tex]1. l + t + 2b = s \\ 2 + 2 + 2(1) = 6 \\ [/tex]
the cost of sandwich is $6
Miguel rode his bike to work which was 15 miles from home. However he was too tired to ride back so he got a ride in a
car from a co-worker. He spent a total of 2 hours traveling. The average speed of traveling by car was 3 times faster
than on his bike. What was Miguel's average speed on his bike and in the car?
Answer:
Bike: 10 miles per hour
Car: 30 miles per hour
Step-by-step explanation:
He spent: 2h/(1+3) = 0,5h by car and 0,5h x 3 = 1,5h by bike
The car is: 15 miles/ 0,5h = 30 miles/h
The bike is: 15 miles/ 1,5h = 10 miles/h
pls help, last question. the one circled in red
On solving the provided question, we can say that - in the linear equation y = 1/2x + 5, slope, m = 1/2
What is a linear equation?The algebraic equation y=mx+b is known as a linear equation. B is the y-intercept, and m is the slope. The previous sentence, where y and x are variables, is commonly referred to as a "linear equation in two variables." Bivariate linear equations are those that contain two variables in them. The linear equations 2x - 3 = 0, 2y = 8, m + 1 = 0, x/2 = 3, x + y = 2, and 3x - y + z = 3 are examples. When an equation has the formula y=mx+b, with m denoting the slope and b the y-intercept, it is referred to as being linear.
here,
in the linear equation =>
y = +1/2x + 5
on comparing with y = mx +c
slope, m = 1/2
and, c= +5
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a line has a slope of 5. it passes through the points (-5, -1) and (x, 9). what is the value of x?
A line has a slope of 5. it passes through the points (-5, -1) and (x,9) than the value of x is -3
We are going to use the fact that when a line passes through two points : [tex](x1,y1) and (x2,y2)[/tex]
the slope is given by the following formula:
[tex]slope=y2-y1/x2-x1[/tex]
In the present case, the slope is 5 and the points are (-5, -1) and (x, 9)
Hence,
[tex]5=9-(-1)/x-(-5)[/tex]
[tex]5=10/x+5\\x+5=10/5\\x+5=2\\x=-3[/tex]
Thus, the value of x is -3 when it travels between the coordinates (-5, -1) and (x, 9).
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Help please ????????????
Answer:
700 i think-
Step-by-step explanation:
Solid fats are more likely to raise blood cholesterol levels than liquid fats. Suppose a nutritionist analyzed the percentage of saturated fat for a sample of 6 brands of stick margarine (solid fat) and for a sample of 6 brands of liquid margarine and obtained the following results: Exam Image Exam Image We want to determine if there a significant difference in the average amount of saturated fat in solid and liquid fats. What is the test statistic
Answer:
[tex]t = 31.29[/tex]
Step-by-step explanation:
Given
[tex]\begin{array}{ccccccc}{Stick} & {25.8} & {26.9} & {26.2} & {25.3} & {26.7}& {26.1} \ \\ {Liquid} & {16.9} & {17.4} & {16.8} & {16.2} & {17.3}& {16.8} \ \end{array}[/tex]
Required
Determine the test statistic
Let the dataset of stick be A and Liquid be B.
We start by calculating the mean of each dataset;
[tex]\bar x =\frac{\sum x}{n}[/tex]
n, in both datasets in 6
For A
[tex]\bar x_A =\frac{25.8+26.9+26.2+25.3+26.7+26.1}{6}[/tex]
[tex]\bar x_A =\frac{157}{6}[/tex]
[tex]\bar x_A =26.17[/tex]
For B
[tex]\bar x_B =\frac{16.9+17.4+16.8+16.2+17.3+16.8}{6}[/tex]
[tex]\bar x_B =\frac{101.4}{6}[/tex]
[tex]\bar x_B =16.9[/tex]
Next, calculate the sample standard deviation
This is calculated using:
[tex]s = \sqrt{\frac{\sum(x - \bar x)^2}{n-1}}[/tex]
For A
[tex]s_A = \sqrt{\frac{\sum(x - \bar x_A)^2}{n-1}}[/tex]
[tex]s_A = \sqrt{\frac{(25.8-26.17)^2+(26.9-26.17)^2+(26.2-26.17)^2+(25.3-26.17)^2+(26.7-26.17)^2+(26.1-26.17)^2}{6-1}}[/tex]
[tex]s_A = \sqrt{\frac{1.7134}{5}}[/tex]
[tex]s_A = \sqrt{0.34268}[/tex]
[tex]s_A = 0.5854[/tex]
For B
[tex]s_B = \sqrt{\frac{\sum(x - \bar x_B)^2}{n-1}}[/tex]
[tex]s_B = \sqrt{\frac{(16.9 - 16.9)^2+(17.4- 16.9)^2+(16.8- 16.9)^2+(16.2- 16.9)^2+(17.3- 16.9)^2+(16.8- 16.9)^2}{6-1}}[/tex]
[tex]s_B = \sqrt{\frac{0.92}{5}}[/tex]
[tex]s_B = \sqrt{0.184}[/tex]
[tex]s_B = 0.4290[/tex]
Calculate the pooled variance
[tex]S_p^2 = \frac{(n_A - 1)*s_A^2 + (n_B - 1)*s_B^2}{(n_A+n_B-2)}[/tex]
[tex]S_p^2 = \frac{(6 - 1)*0.5854^2 + (6 - 1)*0.4290^2}{(6+6-2)}[/tex]
[tex]S_p^2 = \frac{2.6336708}{10}[/tex]
[tex]S_p^2 = 0.2634[/tex]
Lastly, calculate the test statistic using:
[tex]t = \frac{(\bar x_A - \bar x_B) - (\mu_A - \mu_B)}{\sqrt{S_p^2/n_A +S_p^2/n_B}}[/tex]
We set
[tex]\mu_A = \mu_B[/tex]
So, we have:
[tex]t = \frac{(\bar x_A - \bar x_B) - (\mu_A - \mu_A)}{\sqrt{S_p^2/n_A +S_p^2/n_B}}[/tex]
[tex]t = \frac{(\bar x_A - \bar x_B) }{\sqrt{S_p^2/n_A +S_p^2/n_B}}[/tex]
The equation becomes
[tex]t = \frac{(26.17 - 16.9) }{\sqrt{0.2634/6 +0.2634/6}}[/tex]
[tex]t = \frac{9.27}{\sqrt{0.0878}}[/tex]
[tex]t = \frac{9.27}{0.2963}[/tex]
[tex]t = 31.29[/tex]
The test statistic is 31.29
Jahnay is following this recipe to make cakes. Jahnay uses 780 g of butter. How many cakes is Jahnay making? Recipe: Makes 1 Cake 120 g sugar 130 g butter 260 g flour 3 eggs
Jahnay is making 6.5 cakes from the given ingredients.
What is division?The division in mathematics is one kind of operation. In this process, we split the expressions or numbers into the same number of parts.
Given:
Recipe: Makes 1 Cake = 120 g sugar + 130 g butter + 260 g flour + 3 eggs.
Jahnay is following this recipe to make cakes.
Jahnay uses 780 g of butter.
To find the number of cakes:
Use division operation,
780 ÷ 120,
= 780/120
= 78/12
= 6.5
Therefore, Jahnay makes 6.5 cakes.
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Which of the following is equal to the expression listed below?
27 + 36
A.
9 + (3 × 4)
B.
(9 + 3)(9 + 4)
C.
9(3 + 4)
D.
(9 × 3)(9 × 4)
I really need help with this omg
Answer:
its d kkkkkkkkkkkkkkkkkkkkkk
Block B
0 1 2 3 4 5 6
Each dot on the dot plot represents one household on the block. The numbers represent how many mobile devices are in the
households. When comparing the data sets, which TWO statements are correct?
A)
The number of devices per household varies more on Block B
B)
The median number of devices for Block A and Block B is 5.
Each block has 35 devices.
D)
The greatest number of devices in one household is 6.
E)
The least number of devices in one household is 1
Answer:
a and d
Step-by-step explanation:
Statements the number of devices per household varies more on Block B and the least number of devices in one household is 1 are true.
What is a dot plot?A dot plot, also known as a strip plot or dot chart, is a simple form of data visualization that consists of data points plotted as dots on a graph with an x- and y-axis. These types of charts are used to graphically depict certain data trends or groupings.
Block A:
Number of mobile devices are 15.
Greatest number of devices are 5 and the least number of device is 1.
Median is 3.
Block B:
Number of mobile devices are 15.
Greatest number of devices are 4 and the least number of device is 1.
Median is 2.
Therefore, statement A and E are correct.
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M/5 + 9=11
Solve two step equations
Answer:
m=10
Step-by-step explanation:
m/5+9=11 subtract 9
m/5 = 2 multiply 5 by both sides
m = 10