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3 years ago

I’m confused please help

Mathematics

1 answer:

mart [117]3 years ago

7 0

Answer:

im guessing the answer is 43.7

Step-by-step explanation:

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Seven times the difference of twice a number and nine ...

neonofarm [45]

Answer:

7(2x-9)

Step-by-step explanation:

8 0

3 years ago

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A researcher wants to estimate the percentage of all adults that have used the Internet to seek pre-purchase information in the

lara31 [8.8K]

Answer:

The sample size is 1875.

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:

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

Sampling error of 0.03.

This means that $M = 0.03$

99.74% confidence level

So $\alpha = 0.0026$ , z is the value of Z that has a pvalue of $1 - \frac{0.0026}{2} = 0.9987$ , so $Z = 3$ .

25% of all adults had used the Internet for such a purpose

This means that $\pi = 0.25$

What is the sample size

The sample size is n. So

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

$0.03 = 3\sqrt{\frac{0.25*0.75}{n}}$

$0.03\sqrt{n} = 3\sqrt{0.25*0.75}$

Simplifying by 0.03 both sides

$\sqrt{n} = 100\sqrt{0.25*0.75}$

$(\sqrt{n})^2 = (100\sqrt{0.25*0.75})^2$

$n = 1875$

The sample size is 1875.

7 0

3 years ago

Car Survey In a survey of 3,300 people who owned a certain type of car, 1,155 said they would buy that type of car again. What

satela [25.4K]

Answer:

1155/3300 = 0.35

0.35 * 100 = 35

35%

5 0

3 years ago

Evan, Claire, Jaya and Tim are running a 3km relay race.

Kruka [31]

Answer:

Tim needs to finish 59/90

Step-by-step explanation:

Add together what Evan Claire and Jaya ran

9/10 + 7/9+ 2/3

The common denominator is 90

9/10 (9/9) +7/9 *10/10 + 2/3 *30/30

81/90 + 70/90 + 60/90

211/90

We need 3 km = 3 *90/90 = 270 /90

270/90 - 211/90 = 59/90

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4 years ago

Whats 3480+ 92719384

nikitadnepr [17]

92722864

Hope this helps ya

3 0

4 years ago

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