Which graph represents y 2 -2x + 3?<br> OA)<br> OB)<br> OC)<br> OD

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard devia

Arturiano [62]

Answer:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (2)

And on this case we have that ME =+5 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

4 0

2 years ago

Find the value of x. (Picture attached.)

Svet_ta [14]

Here, triangle AEN and ALG are similar.

We know that the ratio of corresponding sides of two similar triangles are equal. So,

$\frac{21}{42} =\frac{2x-9}{(2x-9)+(x+7)}\\\\\frac{1}{2} =\frac{2x-9}{3x-2}\\\\ 3x-2=4x-18\\\\-2+18=4x-3x\\\\16=x\\\\x=16\\$

5 0

2 years ago

Lauri is picking out material for her new quilt. At the fabric store, there are 1919 solids, 99 striped prints, and 1212 floral

Masteriza [31]

Answer:

1,79,07,120 ways

Step-by-step explanation:

Ways in which 3 solids can be chosen from 19 solids = 19 c 3

33 striped prints can be chosen from 99 striped prints in 9 c 3 ways

33 floral prints can be chosen from 121 floral prints in 12 c 33 ways

So, total ways = (19 c 3) (9 c 3) (12 c 3)

(969) (84) (220)

1,79,07,120

7 0

2 years ago

It is proposed to build a raft of pine logs for carrying a cargo on a river. The cargo will weigh 500 kg, and it must be kept en

siniylev [52]

Answer:

They will need 200kg of pine logs.

Gauge pressure in the tank = 24045.29 Pa

Absolute pressure= 125370.29Pa

Step-by-step explanation:

Full question:sp.gr=0.8.The fluid in the nanometer is ethyl iodide with sp.gr =1.93. The manometric fluid height is 50 inches. What is the gauge pressure and absolute pressure in the tank?

Converting 50inches to metres. Multiply by 0.0254

50×0.0254=1.27m

Gauge pressure in tank is given by:

P = pgh

Where p= density,g= acceleration due to gravity, h= height

P= 1.93× 1000× 9.81× 1.27= 24045.29Pa

Absolute pressure=Ptotal= Pliquid + Patm

Absolute pressure =24045.29 + 101325=125370.29pa

6 0

3 years ago

A teacher gave a test with 50 questions, each worth the same number of points. Donovan got 39 out of 50 questions right. Marci's

bearhunter [10]

Answer:

49 all you have to do is add 10 to 39

4 0

2 years ago

Read 2 more answers

Which graph represents y 2 -2x + 3? OA) OB) OC) OD