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3 years ago

Earth’s diameter at the equator is 7,926 miles. Find the distance around the Earth at the equator.

Mathematics

1 answer:

Doss [256]3 years ago

7 0

Answer:

24,900 miles

Step-by-step explanation:

Circumference = pi × d

Pi × 7926

24,900.263372352

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A researcher wishes to estimate the percentage of adults who support abolishing the penny. What size sample should be obtained i

Scorpion4ik [409]

Answer:

a) We need a sample size of at least 3109.

b) We need a sample size of at least 4145.

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:

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

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

(a) he uses a previous estimate of 25%?

we need a sample of size at least n.

n is found when $M = 0.02, \pi = 0.25$ . So

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

$0.02 = 2.575\sqrt{\frac{0.25*0.75}{n}}$

$0.02\sqrt{n} = 2.575\sqrt{0.25*0.75}$

$\sqrt{n} = \frac{2.575\sqrt{0.25*0.75}}{0.02}$

$(\sqrt{n})^{2} = (\frac{2.575\sqrt{0.25*0.75}}{0.02})^{2}$

$n = 3108.1$

We need a sample size of at least 3109.

(b) he does not use any prior estimates?

When we do not use any prior estimate, we use $\pi = 0.5$

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

$0.02 = 2.575\sqrt{\frac{0.5*0.5}{n}}$

$0.02\sqrt{n} = 2.575\sqrt{0.5*0.5}$

$\sqrt{n} = \frac{2.575\sqrt{0.5*0.5}}{0.02}$

$(\sqrt{n})^{2} = (\frac{2.575\sqrt{0.5*0.5}}{0.02})^{2}$

$n = 4144.1$

Rounding up

We need a sample size of at least 4145.

8 0

3 years ago

Andy drove 825 miles to California. The trip takes him 17 hours. He uses 38 gallons of gas on the trip, which cost him $125

babunello [35]

48 is the average speed

he uses 7.3 dollars per hour

6.6 per mile

21.7 gallons per mile

3.20 dollars per gallon of gas

these are the answers I could get

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2 years ago

James bought a house that needs repairs in the 24 ft by 15 ft back yard. He

son4ous [18]

Answer:

below

Step-by-step explanation:

area to be repaired = 24*15=360ft^2

1 bag = 2ft^2

? 360ft^2

360/2 = 180 bags needed

cost of bags = 180*24.95=4491$

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2 years ago

There are 11 blue marbles and 7 red

Rufina [12.5K]

Since the blue marbles are 11 and the red marbles are 7 you start will the red marbles first because the question say red marbles to blue marbles
7:11

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1 year ago

URGENT PLEASE HELP <br><br> Which of the following tables represents a relation that is a function?

NARA [144]

The answer is A because the x has different numbers

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3 years ago