Identify the sampling designs that use voluntary response sampling. Check all that apply.
A pharmaceutical company advertises for subjects to participate in an online survey about insulin pumps for diabetics.

An online poll is created for sports fans to vote on the winner for the Super Bowl.

Each employee is given a mandatory survey to complete about health benefits.

After each customer service call, callers are asked to stay on the line to complete a brief satisfaction survey.

A census taker randomly calls homes to gather data about household income and family demographics.

A used car dealer surveys potential customers about the type of car they are interested in so he can plan his future inventory.


2,3,6

Answer:

D Replace on equation with sum /difference of both equations

The systems are still the same

Step-by-step explanation:

5x + y = 3

4x - 7y = 8

Subtract the second equation from the first

5x + y = 3

-(4x - 7y = 8)

-----------------

x    +8y = -5

The second equation in system B is the first equation in system a minus the second equation in system A

We added the same thing to each side of the equation so the the system is still the same

Answer:

Click the graph in Quadrant 1

Step-by-step explanation:

This graph is bigger in side length.

Answer:

.73 per pound

Step-by-step explanation:

Take the total cost and divide by the number of pounds

4.38/ 6

.73 per pound

Answer:

325 pencils, 650 markers, 975 pens.

Answer:

4 3/4 cups PLEASE MARK ME BRAINLIEST

Step-by-step explanation:

Bowl = 8 cups

Armando first used 2 1/2 cups of flour. So, we need to do 8 - 2 1/2.

8 - 2 1/2 = 8/1 - 5/2

Find the common denominator:

8/1 - 5/2 = 8 x 2/1 x 2 - 5 x 1/2 x 1 = 16/2 - 5/2

Find the final answer:

16/2 - 5/2 = 11/2 = 5 1/2

Then, Armando used 3/4 cups of sugar. So, we need to do 5 1/2 - 3/4.

5 1/2 - 3/4 = 11/2 - 3/4

Find the common denominator:

11/2 - 3/4 = 11 x 2/2 x 2 - 3 x 1/4 x 1 = 22/4 - 3/4

Find the final answer:

22/4 - 3/4 = 19/4 = 4 3/4

Finally, Armando used 1/3 cup of butter. So, we need to do 4 3/4 - 1/3.

4 3/4 - 1/3 = 19/4 - 1/3

Find the common denominator:

19/4 - 1/3 = 19 x 3/4 x 3 - 1 x 4/3 x 4 = 57/4 - 4/12

Find the final answer:

57/4 - 4/12 = 53/12 = 4 5/12

If u like my explanation then plz follow me for more solutions

Answer:

a. 1.44

Step-by-step explanation:

We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 40%.

At the null hypothesis, it is tested if the proportion is of at most 40%, that is:

[tex]H_0: p \leq 0.4[/tex]

At the alternative hypothesis, it is tested if the proportion is of more than 40%, that is:

[tex]H_1: p > 0.4[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

0.4 is tested at the null hypothesis:

This means that [tex]p = 0.4, \sigma = \sqrt{0.4*0.6}[/tex]

A random sample of 200 people was taken. 90 of the people in the sample favored Candidate A.

This means that:

[tex]n = 200, X = \frac{90}{200} = 0.45[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.45 - 0.4}{\frac{\sqrt{0.4*0.6}}{\sqrt{200}}}[/tex]

[tex]z = 1.44[/tex]

Thus the correct answer is given by option a.

2=4x+y

y=2-4x

Александр Мазепов

Step-by-step explanation:

Step 1:  Solve for y

[tex]2 = 4x + y[/tex]

[tex]2 - 4x = 4x + y - 4x[/tex]

[tex]y = 2 - 4x[/tex]

Step 2:  Solve for x

[tex]2 - 2 - 4x = 0 - 2[/tex]

[tex]-4x / -4 = -2 / -4[/tex]

[tex]x = 1/2[/tex]

Step 3:  Solve for y

[tex]y = 2 - 4(0)[/tex]

[tex]y = 2[/tex]

Step 4:  Graph the equation

Graph the x-intercept, (1/2, 0), the y-intercept, (0, 2) and draw a line between them.  Look at the attached picture for the graph:

Assuming the car's speed [tex]\frac{630}{14}=45\mathrm{mph}[/tex] does not change, the car will travel [tex]45\cdot42=\boxed{1890}[/tex] miles.

Hope this helps :)

Answer: 240 minutes

Step-by-step explanation:

Concept:

Here, we need to know the idea of unit conversion.

Unit conversion is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.

1 hour = 60 minutes

Solve:

1 hour = 60 minutes

4 hours = 4 × 60 = 240 minutes

Hope this helps!! :)

Please let me know if you have any questions

Answer:

look at the value of f(x) carefully when we put 7 from x the x take 2 value

Step-by-step explanation:

And g(x) function take 4 value. please look at the first option it has extra 2 so 2 plus 2 equal to 4 this means that the answer might be A. But look at D option it multiply by 2 so D option might be correct answer but we need some info and I want to continue. When I put 1 from x f(x)=1 and g(x)= 2 but when we look at the first option it is 1+2 equal to 3 but it must be 2 so the correct answer is not A and the correct answer is D

Answer:

Step-by-step explanation:

A = (2)(3.14)(2)(4) + (2)(3.14)(2^2)

A = 75.36 in

Answer:

False

Step-by-step explanation:

To find the inverse of a function, switch the variables and solve for y.

The inverse of f(n)=-(n+1)^3:

[tex]y=-(n+1)^3[/tex]

[tex]n=-(y+1)^3[/tex]

[tex]\sqrt[3]{n} =-(y+1)[/tex]

[tex]\sqrt[3]{n} =-y-1[/tex]

[tex]\sqrt[3]{n} +1=-y[/tex][tex]-(\sqrt[3]{n} +1)=y[/tex]

[tex]-\sqrt[3]{n} -1=y[/tex]

Answer:

False

Step-by-step explanation:

Answer:

1/3

Step-by-stepi

===============================================

Explanation:

Add up the values to get

1.96+1.81+1.97+1.83+1.87+1.84+1.85+1.94+1.96+1.81+1.86+1.95+1.89= 24.54

Then divide over 13 (the number of values) to get 24.54/13 = 1.8876923 which is approximate.

So the mean is approximately 1.8876923

---------------------

Now make a spreadsheet as shown below

We have the first column as the x values, which are the original numbers your teacher provided. The second column is of the form (x-M)^2, where M is the mean we computed earlier. We subtract off the mean and square the result.

After we compute that column of (x-M)^2 values, we add them up to get what is shown in the highlighted yellow cell at the bottom of the column.

That sum is approximately 0.04403076924

Next, we divide that over n-1 = 13-1 = 12

0.04403076924 /12 = 0.00366923077

That is the sample variance. Apply the square root to this to get the sample standard deviation. This is the point estimate of the population standard deviation. As the name implies, it works for samples that estimate population parameters.

sqrt(0.00366923077) = 0.06057417576822

This rounds to 0.061 which is the final answer.

Answer:

It's letter b

Step-by-step explanation:

I hope this help

Angles C and D are supplementary, or they add up to 180.

b = 180 - 75 - (180 - 127)

Hope this helps!

Answer:

Step-by-step explanation:

∠C + ∠D = 180   {Linear pair}

∠C + 127  = 180

           ∠C = 180 - 127

In ΔABC ,

∠A + ∠B + ∠C = 180   {angle sum property of triangle}

∠B = 180 - ∠A - ∠C

b = 180 - 75 - (180 - 127)

Answer:

3x ( x+2)(x^2−2x+4)

Step-by-step explanation:

3x^4 + 24x.

Factor out the greatest common factor

3x*x^3 + 3x*8

3x(x^3+8)

Then factor the cubic term

The sum of cubes is a^3+b^3=(a+b)(a^2−ab+b^2)

3x ( x+2)(x^2−2x+4)

I'm going to assume that you mean to say that i = √(-1) is a root of the auxiliary equation. That is, if the Cauchy-Euler DE is

x ²y'' + axy' + by = 0

then the auxiliary equation obtained by substituting y = xᵐ is

x ² (m (m - 1) xᵐ ⁻ ²) + ax (m xᵐ ⁻ ¹) + bxᵐ = 0

which reduces to

m (m - 1) + am + b = 0

or

m ² + (a - 1) m + b = 0

By the fundamental theorem of algebra, we can write the quadratic in terms of its roots r₁ and r₂,

(m - r₁) (m - r₂) = 0

Given that one root is the imaginary unit i, and the coefficients of the aux. equation are real, it follows that the other root is -i, because complex roots must occur with their conjugates. So we have as our aux. equation,

(m - i ) (m + i ) = 0

or

m ² + 1 = 0

Then a - 1 = 0 and b = 1, so that the given root and general solution correspond to the DE,

x ²y'' + xy' + y = 0

Answer:

nada está bien gana bien.

Answer:

no solution

Step-by-step explanation:

multiply 2 and get 2x^2+18-4=0

combine like terms

2x^2+14=0

subtract 14

2x^2=-14

there can't be a square root of a negative number so there's no solution

Answer:

x = ±i sqrt(7)

Step-by-step explanation:

2(x^2+9)-4=0

Add 4 to each side

2(x^2+9)-4+4=0+4

2(x^2+9)=4

Divide by 2

2(x^2+9)/2=4/2

(x^2+9)=2

Subtract 9 from each side

x^2 +9-9 = 2-9

x^2 = -7

Taking the square root of each side

sqrt(x^2) =sqrt(-7)

x = sqrt(-1 *7)

x = ±i sqrt(7)

1099.56m² is the surface area of a cylinder that has a radius of 7 m and a height of 18 m.

Answer:

35

Step-by-step explanation:

The pattern is adding powers of 2.

4+1=5 (exception)

5+2=7

7+4=11

11+8=19

19+16=35

Answer:

35

Step-by-step explanation:

4 + 1 = 5

5 + (1 × 2) = 5 +2 =7

7 + (2×2) = 7 + 4 = 11

11 +(4×2) = 11 + 8 = 19

19 + (8×2) = 19 + 16 = 35

Let x(t) denote the amount of salt (in kg) in the tank at time t. The tank starts with 18 kg of salt, so x (0) = 18.

The solution is drained from the tank at a rate of 90 L/min, so that the amount of salt in the tank changes according to the differential equation

dx(t)/dt = - (x(t) kg)/(9000 L) × (90 L/min) = -1/100 x(t) kg/min

or, more succintly,

x' = -1/100 x

This equation is separable as

dx/x = -1/100 dt

Integrating both sides gives

∫ dx/x = -1/100 ∫ dt

ln|x| = -1/100 t + C

x = exp(-1/100 t + C )

x = C exp(-t/100)

(a) Using the initial condition x (0) = 18, we find

18 = C exp(0)   ==>   C = 18

so that

x(t) = 18 exp(-t/100)

(b) After 20 minutes, we have

x (20) = 18 exp(-20/100) = 18 exp(-1/5) ≈ 14.74

so the tank contains approximately 14.74 kg of salt after this time.

Answer:

Step-by-step explanation:

Let's begin calculating the MPH for Fran.: Joanne's MPH is 250 / 2.5 = 100 MPH.

Now I'm going to subtract the 100 MPH by Fran. going 10 MPH less: 100 - 10 = 90.

I can't see the bottom part of the graph, so based on the MPH, it might be X, if you could put a better picture it would be better!

First check the characteristic solution: the characteristic equation for this DE is

r ² - 3r + 2 = (r - 2) (r - 1) = 0

with roots r = 2 and r = 1, so the characteristic solution is

y (char.) = C₁ exp(2x) + C₂ exp(x)

For the ansatz particular solution, we might first try

y (part.) = (ax + b) + (cx + d) exp(x) + e exp(3x)

where ax + b corresponds to the 2x term on the right side, (cx + d) exp(x) corresponds to (1 + 2x) exp(x), and e exp(3x) corresponds to 4 exp(3x).

However, exp(x) is already accounted for in the characteristic solution, we multiply the second group by x :

y (part.) = (ax + b) + (cx ² + dx) exp(x) + e exp(3x)

Now take the derivatives of y (part.), substitute them into the DE, and solve for the coefficients.

y' (part.) = a + (2cx + d) exp(x) + (cx ² + dx) exp(x) + 3e exp(3x)

… = a + (cx ² + (2c + d)x + d) exp(x) + 3e exp(3x)

y'' (part.) = (2cx + 2c + d) exp(x) + (cx ² + (2c + d)x + d) exp(x) + 9e exp(3x)

… = (cx ² + (4c + d)x + 2c + 2d) exp(x) + 9e exp(3x)

Substituting every relevant expression and simplifying reduces the equation to

(cx ² + (4c + d)x + 2c + 2d) exp(x) + 9e exp(3x)

… - 3 [a + (cx ² + (2c + d)x + d) exp(x) + 3e exp(3x)]

… +2 [(ax + b) + (cx ² + dx) exp(x) + e exp(3x)]

= 2x + (1 + 2x) exp(x) + 4 exp(3x)

… … …

2ax - 3a + 2b + (-2cx + 2c - d) exp(x) + 2e exp(3x)

= 2x + (1 + 2x) exp(x) + 4 exp(3x)

Then, equating coefficients of corresponding terms on both sides, we have the system of equations,

x : 2a = 2

1 : -3a + 2b = 0

exp(x) : 2c - d = 1

x exp(x) : -2c = 2

exp(3x) : 2e = 4

Solving the system gives

a = 1, b = 3/2, c = -1, d = -3, e = 2

Then the general solution to the DE is

y(x) = C₁ exp(2x) + C₂ exp(x) + x + 3/2 - (x ² + 3x) exp(x) + 2 exp(3x)

Answer:

b

Step-by-step explanation:

i had it

Answer:

8. 72% × 850

= 72/100 × 850

= 72 × 8,5

= 612 ( b )

9. Poin B = 4 ( b )

Answer:

8. B

9. B

10. C

Step-by-step explanation:

8. To find 72% of 850, you would multiply 0.72 x 850. When you do that, it gives you 612.

9. B is on the number 4.

10. The expression is asking, "What is the absolute value of 28?". Absolute value means that the number inside will always be positive. For example, if it was -28, the absolute value would turn to 28. Since the question has 28 already positive, there is no change, so the answer would be 28.

Answer:

464 $

Step-by-step explanation: