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3 years ago

Can someone help me with this question?

Mathematics

1 answer:

Likurg_2 [28]3 years ago

6 0

I’d say the answer is 72

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If you wanted to estimate the mean height of all students at a university, which of the following sampling strategies would be b

xenn [34]

Answer:

Step-by-step explanation:

Hello!

To take a sample to estimate the mean height of all students at a university and that the value you reach is statistically valid you need the sampling method to be random and representative of the whole population, in this example, all university students.

a. Measure the heights of 50 students found in the gym during basketball intramurals.

This method is not the best because you would be sampling only basketball players leaving all other students of the university outside, i.e. your sample will not be representative of all the students, just the ones that play basketball.

b. Measure the heights of all engineering majors.

This method is not good, the sample only represents engineering mayors meaning that it does not include the students of any other subjects.

c. Measure the heights of the students selected by choosing the first name on each page of the campus phone book.

With this method you choose students regardless of the sport or major they're are taking, it is more representative of the population of university students, of the three options, this is the best one.

I hope it helps!

4 0

3 years ago

What is the name of the segment inside a triangle

Len [333]

Answer:

altitude is the answer

6 0

3 years ago

Read 2 more answers

The average cost of tuition and room and board at a small private liberal arts college is reported to be $8,500 per term, but a

Tom [10]

Answer:

H₀: µ ≤ $8,500; H₁: µ > $8,500

z= +1.645

Step-by-step explanation:

From the given problem As average cost of tuition and room and board at a small private liberal is less than the financial administrator As hypothesis is true.

As standard deviation is $ 1,200

α = 0.05

H₀: µ ≤ $8,500

if the null hypothesis is true then value for critical z is +1.645.

6 0

2 years ago

Problem 4: Let F = (2z + 2)k be the flow field. Answer the following to verify the divergence theorem: a) Use definition to find

Viktor [21]

Given that you mention the divergence theorem, and that part (b) is asking you to find the downward flux through the disk $x^2+y^2\le3$ , I think it's same to assume that the hemisphere referred to in part (a) is the upper half of the sphere $x^2+y^2+z^2=3$ .

a. Let $C$ denote the hemispherical <u>c</u>ap $z=\sqrt{3-x^2-y^2}$ , parameterized by

$\vec r(u,v)=\sqrt3\cos u\sin v\,\vec\imath+\sqrt3\sin u\sin v\,\vec\jmath+\sqrt3\cos v\,\vec k$

with $0\le u\le2\pi$ and $0\le v\le\frac\pi2$ . Take the normal vector to $C$ to be

$\vec r_v\times\vec r_u=3\cos u\sin^2v\,\vec\imath+3\sin u\sin^2v\,\vec\jmath+3\sin v\cos v\,\vec k$

Then the upward flux of $\vec F=(2z+2)\,\vec k$ through $C$ is

$\displaystyle\iint_C\vec F\cdot\mathrm d\vec S=\int_0^{2\pi}\int_0^{\pi/2}((2\sqrt3\cos v+2)\,\vec k)\cdot(\vec r_v\times\vec r_u)\,\mathrm dv\,\mathrm du$

$\displaystyle=3\int_0^{2\pi}\int_0^{\pi/2}\sin2v(\sqrt3\cos v+1)\,\mathrm dv\,\mathrm du$

$=\boxed{2(3+2\sqrt3)\pi}$

b. Let $D$ be the disk that closes off the hemisphere $C$ , parameterized by

$\vec s(u,v)=u\cos v\,\vec\imath+u\sin v\,\vec\jmath$

with $0\le u\le\sqrt3$ and $0\le v\le2\pi$ . Take the normal to $D$ to be

$\vec s_v\times\vec s_u=-u\,\vec k$

Then the downward flux of $\vec F$ through $D$ is

$\displaystyle\int_0^{2\pi}\int_0^{\sqrt3}(2\,\vec k)\cdot(\vec s_v\times\vec s_u)\,\mathrm du\,\mathrm dv=-2\int_0^{2\pi}\int_0^{\sqrt3}u\,\mathrm du\,\mathrm dv$

$=\boxed{-6\pi}$

c. The net flux is then $\boxed{4\sqrt3\pi}$ .

d. By the divergence theorem, the flux of $\vec F$ across the closed hemisphere $H$ with boundary $C\cup D$ is equal to the integral of $\mathrm{div}\vec F$ over its interior:

$\displaystyle\iint_{C\cup D}\vec F\cdot\mathrm d\vec S=\iiint_H\mathrm{div}\vec F\,\mathrm dV$

We have

$\mathrm{div}\vec F=\dfrac{\partial(2z+2)}{\partial z}=2$

so the volume integral is

$2\displaystyle\iiint_H\mathrm dV$

which is 2 times the volume of the hemisphere $H$ , so that the net flux is $\boxed{4\sqrt3\pi}$ . Just to confirm, we could compute the integral in spherical coordinates:

$\displaystyle2\int_0^{\pi/2}\int_0^{2\pi}\int_0^{\sqrt3}\rho^2\sin\varphi\,\mathrm d\rho\,\mathrm d\theta\,\mathrm d\varphi=4\sqrt3\pi$

4 0

3 years ago

Write a linear equation to represent the line shown on the graph

sveticcg [70]

Answer:

y=-3x+4

Step-by-step explanation:

it's negative bc the slope is going from left to right. you just have to do rise over run to find the slope.

7 0

3 years ago