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2 years ago

4

Give an example of how you would create a sample from the population of the United States using cluster sampling and stratified

sampling. Then, compare and contrast these two methods.

2 answers:

Tamiku [17]2 years ago

5 0

For both methods, divide a population into groups.
Cluster sampling, select all of the members in some of the groups.Stratified sampling, select a random sample from each group.

trasher [3.6K]2 years ago

4 0

<span>This is the sample response: Divide the US into groups, by state. For cluster sampling, randomly choose twenty states and use the population of those states as the sample. For stratified sampling, randomly choose 10,000 people from every state as the sample.</span>

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Tickets for a concert were \$5$5dollar sign, 5 for each child and \$8$8dollar sign, 8 for each adult. At one of the concerts, ea

OlgaM077 [116]

Answer:

Step-by-step explanation:

Let c represent the number of children that attended the concert.

Let a represent the number of adults that attended the concert.

At one of the concerts, each adult brought 4 children with them, and 10 children attended without an adult. This means that the number of children that attended is

c = 4a + 10

Tickets for a concert were $5 for each child and $8 for each adult. The total ticket sales were $1730. It means that

5c + 8a = 1730

Therefore, the systems of equations that can be solved to determine the number of children, c, and adults that attended the concert is

c = 4a + 10

5c + 8a = 1730

4 0

2 years ago

Factorise 6x² -5x -21

Alex Ar [27]

I think it’s this but I’m not sure

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2 years ago

Which test point holds true for y − 2x ≤ 1?

CaHeK987 [17]

So in order to find the correct answer, we can just easily plug in the values to check which ordered pair matches the given inequality above. So based on my solutions, the correct answer would be the last pair.
<span> y − 2x ≤ 1
0 - 2(5)</span> ≤ 1
0-10 ≤ 1
-10 ≤ 1
Hope this answer helps.

3 0

2 years ago

The length of the day in Boulder (Latitude 40 N) can be modeled approximately by l(t) = −3 cos ( 2π 365 (t + 10)) + 12 where l i

Harman [31]

Answer:

(a) I(355)=9

(b) I'(265)=−0.05163

(c) The l′(t) is largest at 81.25.

Step-by-step explanation:

The given function is

$I(t)=-3\cos (\frac{2\pi}{365}(t+10))+12$

where I(t) the length of the day in Boulder and l is given in hours and t is the day of the year.

(a)

Substitute t=355 in given function.

$I(355)=-3\cos (\frac{2\pi}{365}(355+10))+12$

$I(355)=-3\cos (2\pi)+12$

$I(355)=-3(1)+12$

$I(355)=9$

Therefore, the value of I(355) is 9. It means the length of the day in Boulder is 9 hours at 355 day of the year.

(b)

Differentiate the given function with respect to t.

$I'(t)=-3(-\sin (\frac{2\pi}{365}(t+10)))(\frac{2\pi}{365})$

$I'(t)=\frac{6\pi}{365}\sin (\frac{2\pi}{365}(t+10))$

Substitute t=265 in the above function.

$I'(t)=\frac{6\pi}{365}\sin (\frac{2\pi}{365}(265+10))$

$I'(265)\approx −0.05163$

Therefore, the value of I'(265) is −0.05163. It means the length of the day in Boulder decreased by 0.05163 hours at 265 day of the year.

(c)

Differentiate the I'(t) function with respect to t.

$I''(t)=\frac{6\pi}{365}\cos (\frac{2\pi}{365}(t+10))(\frac{2\pi}{365})$

$I''(t)=\frac{12\pi^2}{(365)^2}\cos (\frac{2\pi}{365}(t+10))$

Equate $I''(t)=0$ to find critical points.

$\frac{12\pi^2}{(365)^2}\cos (\frac{2\pi}{365}(t+10))=0$

$\cos (\frac{2\pi}{365}(t+10))=0$

$\cos (\frac{2\pi}{365}(t+10))=\cos (\frac{\pi}{2})$

On comparing both sides we get

$\frac{2\pi}{365}(t+10)=\frac{\pi}{2}$

$t+10=\frac{\pi}{2}\times \frac{365}{2\pi}$

$t+10=\frac{365}{4}$

$t=\frac{365}{4}-10$

$t=81.25$

Check the value of the function I'''(t) at t=81.25.

Since $I'''(81.25)=-0.0000153$ , therefore the value of l′(t) is largest at 81.25.

4 0

2 years ago

Biologists notice an alarming trend in the walleye population in Lake Erie. Despite annual restocking rates of 2 million fish, t

JulsSmile [24]

Answer:

f(x) = 26000000(.85)^x + 2,000,000

f(1) = 26,000,000

f(2) = 24100000

f(3) = 22485000

f(4) = 21112250

Geometric, it is going down by a %, not a fixed number

Year 5, less pollution

f(8) = 9,084,753.65

Step-by-step explanation:

f(2) = 26,000,000 (.85)^2 + 2,000,000

f(2) = 24100000

f(3) = 26,000,000 (.85)^3 + 2,000,000

f(3) = 22485000

f(4) = 26,000,000(.85)^4 + 2,000,000

f(4) = 21,112,250

f(8) = 26,000,000(.85)^8 + 2,000,000

f(8) = 9,084,753.65

5 0

2 years ago