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3 years ago

7

Answer the question and explain your answer. I will be marking brainiest! If you have the correct answer and explain why it’s co

rrect, I will probably pick YOU as brainiest! :)

1 answer:

cestrela7 [59]3 years ago

7 0

Answer:

A = 200.96 sq ft

Step-by-step explanation:

formula for area of a circle: A = π·r²

A = (3.14)·(8²)

A = 64·(3.14)

A = 200.96

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A doctor at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she

Nataly_w [17]

Answer:

The minimum sample size needed is $n = (\frac{1.96\sqrt{\sigma}}{4})^2$ . If n is a decimal number, it is rounded up to the next integer. $\sigma$ is the standard deviation of the population.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.645.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

How large a sample must she select if she desires to be 90% confident that her estimate is within 4 ounces of the true mean?

A sample of n is needed, and n is found when M = 4. So

$M = z\frac{\sigma}{\sqrt{n}}$

$4 = 1.96\frac{\sigma}{\sqrt{n}}$

$4\sqrt{n} = 1.96\sqrt{\sigma}$

$\sqrt{n} = \frac{1.96\sqrt{\sigma}}{4}$

$(\sqrt{n})^2 = (\frac{1.96\sqrt{\sigma}}{4})^2$

$n = (\frac{1.96\sqrt{\sigma}}{4})^2$

The minimum sample size needed is $n = (\frac{1.96\sqrt{\sigma}}{4})^2$ . If n is a decimal number, it is rounded up to the next integer. $\sigma$ is the standard deviation of the population.

4 0

3 years ago

What is the reasoning for this statement?

Dahasolnce [82]

Answer:

there is a black photo

Step-by-step explanation:

make sure to check properly

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3 years ago

Which one would it be?

gayaneshka [121]

Answer:

yES 2:3

Step-by-step explanation:

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4 0

3 years ago

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HELPPPP what is the estimated measure of angle DAC?<br> (the last answer choice is 90°)

elena-14-01-66 [18.8K]

The answer is 110 degrees because a right angle is 90 and thats obtuse so its more than 90 and 110 is the only one more than 90

4 0

4 years ago

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A right triangle has legs of length 4x and 20x. What is an expression for the hypotenuse of the right triangle

kherson [118]

Answer:

$4x\sqrt{26}$ .

Step-by-step explanation:

Given information:

$Leg_1=4x$

$Leg_2=20x$

According to the Pythagoras theorem,

$(hypotenuse)^2=(Leg_1)^2+(leg_2)^2$

Using Pythagoras theorem, we get

$(hypotenuse)^2=(4x)^2+(20x)^2$

$(hypotenuse)^2=16x^2+400x^2$

$(hypotenuse)^2=416x^2$

Taking square root on both sides.

$hypotenuse=\sqrt{416x^2}$

$hypotenuse=4x\sqrt{26}$

Hence, the expression of the hypotenuse is $4x\sqrt{26}$ .

5 0

3 years ago