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4 years ago

A right prism has a base in the shape of an octagon. The side length of the octagon is 4 inches. The length of the

Mathematics

2 answers:

shusha [124]4 years ago

5 0

Answer:

927 cn

Step-by-step explanation:

nikitadnepr [17]4 years ago

3 0

Answer:

927 cubic inches

Step-by-step explanation:

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Need help with this struggling a bit.

Kaylis [27]

The answer is A hope it helps plz mark me a brainlest

6 0

3 years ago

Read 2 more answers

Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true

Feliz [49]

Answer:

a) The 95% CI for the true average porosity is (4.51, 5.19).

b) The 98% CI for true average porosity is (4.11, 5.01)

c) A sample size of 15 is needed.

d) A sample size of 101 is needed.

Step-by-step explanation:

a. Compute a 95% CI for the true average porosity of a certain seam if the average porosity for 20 specimens from the seam was 4.85.

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.025 = 0.975$ , so $z = 1.96$

Now, find the margin of error M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 1.96*\frac{0.78}{\sqrt{20}} = 0.34$

The lower end of the interval is the sample mean subtracted by M. So it is 4.85 - 0.34 = 4.51

The upper end of the interval is the sample mean added to M. So it is 4.35 + 0.34 = 5.19

The 95% CI for the true average porosity is (4.51, 5.19).

b. Compute a 98% CI for true average porosity of another seam based on 16 specimens with a sample average of 4.56.

Following the same logic as a.

98% C.I., so $z = 2.327$

$M = 2.327*\frac{0.78}{\sqrt{16}} = 0.45$

4.56 - 0.45 = 4.11

4.56 + 0.45 = 5.01

The 98% CI for true average porosity is (4.11, 5.01)

c. How large a sample size is necessary if the width of the 95% interval is to be 0.40?

A sample size of n is needed.

n is found when M = 0.4.

95% C.I., so Z = 1.96.

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.4 = 1.96*\frac{0.78}{\sqrt{n}}$

$0.4\sqrt{n} = 1.96*0.78$

$\sqrt{n} = \frac{1.96*0.78}{0.4}$

$(\sqrt{n})^{2} = (\frac{1.96*0.78}{0.4})^{2}$

$n = 14.6$

Rounding up

A sample size of 15 is needed.

d. What sample size is necessary to estimate the true average porosity to within 0.2 with 99% confidence?

99% C.I., so z = 2.575

n when M = 0.2.

$M = z*\frac{\sigma}{\sqrt{n}}$

$0.2 = 2.575*\frac{0.78}{\sqrt{n}}$

$0.2\sqrt{n} = 2.575*0.78$

$\sqrt{n} = \frac{2.575*0.78}{0.2}$

$(\sqrt{n})^{2} = (\frac{2.575*0.78}{0.2})^{2}$

$n = 100.85$

Rounding up

A sample size of 101 is needed.

8 0

4 years ago

Please help!!<br><br> Which system of inequalities is represented by the graph?

kifflom [539]

Answer:

The third option

y < -2x +2

y < or = 1/2x -1

y > or = -4

Step-by-step explanation:

Solved on Desmos graphing calculator ;)

6 0

3 years ago

Two sides of a parallelogram measure 60 centimeters and 40 centimeters. If one angle of the parallelogram measures 132, find the

Serjik [45]

By cosine rule, the length of the longer diagonal is sqrt(60^2 + 40^2 - 2 x 60 x 40 cos 132) = sqrt(8,411.83) = 91.7 cm

The other angle of the parallelogram is 180 - 132 = 48
The length of the shorter diagonal is sqrt(60^2 + 40^2 - 2 x 60 x 40 cos 48) = sqrt(1,988.17) = 44.6 cm

7 0

3 years ago

Read 2 more answers

The following triangle shows the length of each side using expressions.

grigory [225]

Answer:

A). 2(2n+7)+3n

B). 2(2(8)+7)+3(8)
2(16+7)+ 24
2(23)+24
46+24
70

4 0

3 years ago