The inequality 7-2/3 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

3 years ago

1/2 of 3 + 3/4 of 3 +1/2 of 2=

Vedmedyk [2.9K]

=3/2+ 9/4+ 2/2
=1.5+ 2.25+ 1
=4.75

6 0

3 years ago

SHOW WORK PLS. y = x ^ 2 - x - 11 y = - x - 7 solve by substitution!

slava [35]

X^2-x-11=-x-7
X^2-11=-7
X^2=4
X=2 (4 was reduced to 2 after the equation was square rooted)
Pls give brainliest so close to ranking up

3 0

2 years ago

For the given line segment, write the equation of the perpendicular bisector.

Jlenok [28]

Answer:

D) y = -4/5x – 47/10

Step-by-step explanation:

Step 1. Find the midpoint of the segment.

The two end points are (-6, -4) and (-2, 1).

The midpoint is at the average of the coordinates.

(xₚ, yₚ) = ((x₁ + x₂)/2, (y₁ + y₂)/2)

(xₚ, yₚ) = ((-6 - 2)/2, (-4 + 1)/2)

(xₚ, yₚ) = (-8/2, -3/2)

(xₚ, yₚ) = (-4, -3/2)

===============

Step 2. Find the slope (m₁) of the segment

m₁ = (y₂ - y₁)/(x₂ - x₁)

m₁ = (1 - (-4))/(-2 - (-6))

m₁ = (1 + 4)/(-2 + 6)

m₁ = 5/4

===============

Step 3. Find the slope (m₂) of the perpendicular bisector

m₂ = -1/m₁

m₂ = -4/5

====================

Step 4. Find the intercept of the perpendicular bisector

y = mx + b

y = -(4/5)x + b

The line passes through (-4, -3/2).

-3/2 = -(4/5)(-4) + b

-3/2 = 16/5 + b Multiply each side by 10

-15 = 32 + 10 b Subtract 32 from each side

-47 = 10b Divide each side by 10

b = -47/10

===============

Step 5. Write the equation for the perpendicular bisector

y = -4/5x – 47/10

The graph shows the midpoint of your segment at (-4, -3/2) and the perpendicular bisector passing through the midpoint and (0, -47/10).

4 0

3 years ago

Please helppppppppp.....

Lana71 [14]

Answer: B

Step-by-step explanation:

7 0

3 years ago