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3 years ago

7

Select the equivalent expression. (8^-5/2^-2)^-4 = ?

1 answer:

Alchen [17]3 years ago

7 0

Answer:

C. 8^20/2^8

Step-by-step explanation:

(8^5/2²)^4

8^20/2^8

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A sociologist wishes to estimate the percentage of the United States population living in poverty. What size sample should be ob

andriy [413]

Answer:

a) We need a sample size of at least 705.

b) We need a sample size of at least 1692.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a pvalue of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

a) If she uses 1999 estimate of 11.8% obtained from the Current Population Survey.

We need a sample of size at least n

n is found when $M = 0.02, \pi = 0.118$ .

So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.02 = 1.645\sqrt{\frac{0.118*0.882}{n}}$

$0.02\sqrt{n} = 1.645\sqrt{0.118*0.882}$

$\sqrt{n} = \frac{1.645\sqrt{0.118*0.882}}{0.02}$

$(\sqrt{n})^{2} = (\frac{1.645\sqrt{0.118*0.882}}{0.02})^{2}$

$n = 704.08$

Rounding up

We need a sample size of at least 705.

b) She does not use any estimate.

Same thing as above, we just use $\pi = 0.5$ when do not use any estimate.

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.02 = 1.645\sqrt{\frac{0.5*0.5}{n}}$

$0.02\sqrt{n} = 1.645\sqrt{0.5*0.5}$

$\sqrt{n} = \frac{1.645\sqrt{0.5*0.5}}{0.02}$

$(\sqrt{n})^{2} = (\frac{1.645\sqrt{0.5*0.5}}{0.02})^{2}$

$n = 1691.2$

Rounding up

We need a sample size of at least 1692.

4 0

3 years ago

Ahmad made 4 identical necklaces, each having beads and a pendant. The total cost of the beads and pendants for all 4 necklaces

yanalaym [24]

$6.40
All beads and pendants = $19.20, and the beads equal $12.80, so 12.80 + ? = 19.20. So you would use the equation. 19.20 - 12.80, which equals 6.40.

6 0

3 years ago

Graph the image of this figure after a dilation with a scale factor of 12 centered at the point (2, 2) . Use the polygon tool to

Alla [95]

Answer:

Labelled the given figure triangle as A, B and C.

In triangle ABC;

The coordinates of ABC are:

A = (0, 4)

B = (-2, 10) and

C = (-6, 8)

To find the image of this figure after a dilation with a scale factor of $\frac{1}{2}$ centered at the point O=(2, 2).

The rule of dilation with scale factor $\frac{1}{2}$ centered at the point (2, 2) is given by;

$(x, y) \rightarrow (\frac{1}{2}(x-2) +2 , \frac{1}{2}(y-2) +2)$

or

$(x, y) \rightarrow (\frac{1}{2}x+1 , \frac{1}{2}y+1)$

The coordinate of the image of the figure after dilation are;

$A(0, 4) \rightarrow A'(\frac{1}{2}(0)+1 , \frac{1}{2}(4)+1)$ = A'(1, 3)

$B(-2, 10) \rightarrow B'(\frac{1}{2}(-2)+1 , \frac{1}{2}(10)+1)$ = B'(0, 6)

$C(-6, 8) \rightarrow C'(\frac{1}{2}(-6)+1 , \frac{1}{2}(8)+1)$ = C'(-2, 5)

You can see the graph as shown below in the attachment:

5 0

3 years ago

PLEASE HELP THIS WILL GIVE 50 POINT AND BRAINLIEST！！！！！!

KatRina [158]

Answer:

the asnswer is -67463 to the power of 4

Step-by-step explanation:

4 0

2 years ago

F(-5) if(x) - 4x + 2

sashaice [31]

Answer:

22

Step-by-step explanation:

-4(-5)+2

20+2

22

3 0

3 years ago