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3 years ago

How to use permutations and combinations?

1 answer:

8 0

You use permutations for lists where the order matters; and use combinations for groups where the order doesn't matter.

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A Gallup Poll showed that 30% of Americans are satisfied with the way things are going in the United States. Suppose a sample of

mars1129 [50]

The expected number of a distribution is its mean.

The expected number of Americans who are satisfied with the way things are going in the United States is 6
The standard deviation of Americans who are satisfied with the way things are going in the United States is 2.05

The given parameters are:

$\mathbf{p = 30\%}$ --- the proportion that are satisfied

$\mathbf{n = 20}$ --- the sample size

(a) The expected number that are satisfied

This is calculated using:

$\mathbf{E(x) = np}$

So, we have:

$\mathbf{E(x) = 20 \times 30\%}$

$\mathbf{E(x) = 6}$

The expected number of Americans who are satisfied with the way things are going in the United States is 6

(b) The standard deviation of those that are satisfied

This is calculated using:

$\mathbf{\sigma = \sqrt{n \times p \times (1 - p)}}$

So, we have:

$\mathbf{\sigma = \sqrt{20 \times 30\% \times (1 - 30\%)}}$

$\mathbf{\sigma = \sqrt{20 \times 30\% \times 70\%}}$

$\mathbf{\sigma = \sqrt{4.2}}$

$\mathbf{\sigma = 2.05}$

The standard deviation of Americans who are satisfied with the way things are going in the United States is 2.05

Read more about expected value and standard deviations at:

brainly.com/question/17088771

4 0

3 years ago

BRIA is a rectangle. AN=5. NR=x-3. please solve for x, NR, and BI

Lena [83]

Answer:

x=8

NR=5 units

BI=10 units

Step-by-step explanation:

In a rectangle BRIA

AN=5 units

NR=x-3

We have to solve for x , NR and BI.

We know that

Diagonals of rectangle bisect to each other.

BI and AR are the diagonals of rectangle BRIA and intersect at point N.

AN=NR

$5=x-3$

$x=5+3=8$

$x=8$

Substitute the value of x

NR=8-3=5

By property of rectangle

BI=AR=AN+NR=5+5=10 unit

BI=10 units

7 0

3 years ago

I need help on question 2. Any help is appreciated:)

zlopas [31]

All the y values would be 0, since it’s a horizontal line

3 0

3 years ago

700+a=3944-b=c-80=3000

velikii [3]

Answer:

A = 3244

B = 864

C = 3080

Step-by-step explanation:

700 + a = 3944

-700 -700

a = 3244

3944 - b = c - 80 = 3000

c - 80 = 3000

+80 +80

c = 3080

3944 - b = c ---> 3944 - b = 3080

-3944 -3944

-b = -864 ---> $\frac{-b}{-1} = \frac{-864}{-1}$

7 0

3 years ago

A blueprint shows the mater bedroom to be 5 inches long and 3 inches wide. The scale on the blueprint is 2 in : 11 ft. What is t

Anna35 [415]

Answer:

453.75 sq. feet

Step-by-step explanation:

In this question, we are going to calculate the area of a room given the blue print measurement and the actual measurements with the answer being in the actual measurement.

To correctly do this, it is best if the measurements are converted to the actual.

The measurements we’ll be trying to convert is 5 inches by 3 inches with a scale of 2in to 11ft ( same as 1 in to 5.5 ft)

The 5 inches blueprint measurement will be 5 * 5.5 = 27.5 ft

The 3 inches blueprint measurement will be 3 * 5.5 = 16.5 ft

The area in sq. feet will be length * width = 27.5 * 16.5 = 453.75 sq feet

7 0

3 years ago