The answer is 49
Hope this helps
Answer:
a) n = 1037.
b) n = 1026.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
![\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=%5Cpi%20%5Cpm%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
In which
z is the zscore that has a pvalue of ![1 - \frac{\alpha}{2}](https://tex.z-dn.net/?f=1%20-%20%5Cfrac%7B%5Calpha%7D%7B2%7D)
The margin of error is:
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
99% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
(a) Assume that nothing is known about the percentage to be estimated.
We need to find n when M = 0.04.
We dont know the percentage to be estimated, so we use
, which is when we are going to need the largest sample size.
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
![0.04 = 2.575\sqrt{\frac{0.5*0.5}{n}}](https://tex.z-dn.net/?f=0.04%20%3D%202.575%5Csqrt%7B%5Cfrac%7B0.5%2A0.5%7D%7Bn%7D%7D)
![0.04\sqrt{n} = 2.575*0.5](https://tex.z-dn.net/?f=0.04%5Csqrt%7Bn%7D%20%3D%202.575%2A0.5)
![(\sqrt{n}) = \frac{2.575*0.5}{0.04}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%20%3D%20%5Cfrac%7B2.575%2A0.5%7D%7B0.04%7D)
![(\sqrt{n})^{2} = (\frac{2.575*0.5}{0.04})^{2}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E%7B2%7D%20%3D%20%28%5Cfrac%7B2.575%2A0.5%7D%7B0.04%7D%29%5E%7B2%7D)
![n = 1036.03](https://tex.z-dn.net/?f=n%20%3D%201036.03)
Rounding up
n = 1037.
(b) Assume prior studies have shown that about 55% of full-time students earn bachelor's degrees in four years or less.
![\pi = 0.55](https://tex.z-dn.net/?f=%5Cpi%20%3D%200.55)
So
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
![0.04 = 2.575\sqrt{\frac{0.55*0.45}{n}}](https://tex.z-dn.net/?f=0.04%20%3D%202.575%5Csqrt%7B%5Cfrac%7B0.55%2A0.45%7D%7Bn%7D%7D)
![0.04\sqrt{n} = 2.575*\sqrt{0.55*0.45}](https://tex.z-dn.net/?f=0.04%5Csqrt%7Bn%7D%20%3D%202.575%2A%5Csqrt%7B0.55%2A0.45%7D)
![(\sqrt{n}) = \frac{2.575*\sqrt{0.55*0.45}}{0.04}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%20%3D%20%5Cfrac%7B2.575%2A%5Csqrt%7B0.55%2A0.45%7D%7D%7B0.04%7D)
![(\sqrt{n})^{2} = (\frac{2.575*\sqrt{0.55*0.45}}{0.04})^{2}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E%7B2%7D%20%3D%20%28%5Cfrac%7B2.575%2A%5Csqrt%7B0.55%2A0.45%7D%7D%7B0.04%7D%29%5E%7B2%7D)
![n = 1025.7](https://tex.z-dn.net/?f=n%20%3D%201025.7)
Rounding up
n = 1026.
The lateral area would be 298.7 cm².
The lateral area is the area of all of the lateral faces of the pyramid. There are 8 triangles making up the lateral faces. Each has a base of 6.6. The formula for the area of a triangle is
A=1/2bh,
so we still need the height of the triangle.
The height of each lateral triangle is the slant height of the pyramid. The slant height of the pyramid forms a right triangle with the height of the pyramid and the "radius" as it were of the pyramid. Thus we use the Pythagorean theorem:
8²+8²=h²
64+64=h²
128=h²
√128=√(h²)
8√2 = h
Substituting this into our area formula we have:
A=1/2(6.6)(8√2)
We will go ahead and multiply this by 8, since there are 8 lateral faces:
LA=8(1/2)(6.6)(8√2)
LA = 298.7
The answer is.. 23 and 16
Hope this helps!!
Answer:
-15 + 10x
or
10x - 15
(either one works)
Step-by-step explanation:
You mean you just want me to expand it?
Ok.
Multiply -5 by 3 and -2x.
(-5)(3) = -15
(-5)(-2x) = +10x
Add those together:
-15 + 10x
or
10x - 15