-4(1-8n) - 4(8n+4)=x

Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

2 years ago

Miguel run faster than 19 of his teammates what percent of the team is slower than Miguel

nika2105 [10]

Answer:

he is faster than 95% of his team

Step-by-step explanation:

To finde this

First: Add Miguel to his 19 people equals 20 people

Next divide the 19/20

Providing the answer 0.95

to get the percentage multiply the decimal by 100: 0.95*100

= 95%

4 0

3 years ago

Im Giving Brainliest............. Someone Plzz Help?

Alekssandra [29.7K]

Answer:

For the first one 25.925%

The second is 23.333%

The third is 27.27%

Let me know if this helps!

6 0

2 years ago

Given the graphs of f(x) = x – 1 and g(x) = –x – 7, what is the solution to the equation f(x) = g(x)?

Ghella [55]

Answer:

(-3, -4)

Step-by-step explanation:

f(x) = x – 1 and g(x) = –x – 7

f(x) = g(x)

x-1= -x-7
2x= -6
x= -3
f,g= -4

4 0

3 years ago

What is Perpendicular Slice? is up or down or Left to Right I Forgot

Nikolay [14]

Answer:

up and down

Step-by-step explanation:

4 0

3 years ago

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