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3 years ago

Please help will give brainliest

Mathematics

1 answer:

SVEN [57.7K]3 years ago

8 0

Answer:

The diameter is: 8 feet

The radius is: 4 ft.

The area is: 50.27

Step-by-step explanation:

Hope this helps!

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Two years ago Juanita bought 2 shirts for $15 and last year she bought 4 shirts for $45. Assuming the prices will increase linea

AleksandrR [38]

Answer:

This year, Juanita will have to use $75.

Step-by-step explanation:

Because if 2 shirts is $15, 4 shirts will be $30. $45 is $15 more than $30, so the increase is $15. 2*4 is 8, so that will make it 15*4=60. 60+15=75.

8 0

3 years ago

a national survey conducted among a simple random sample of 1,507 adults shows that 56% of americans think the civil war is stil

soldier1979 [14.2K]

$z=4.658\\p_v=P(z > 4.65)=1-P(z < 4.65)=1.581x*10^{-6}$

b) By assuming a significance level of α = 0.05 and observing that $p_v$ > α, we can reject the null hypothesis at this level of significance. And in this instance, it makes sense that more than 50% of Americans believe that the Civil War still has an impact on American politics and political life.

c) The confidence interval at 90% would be shown (0.527;0.593).

About 54% to 59% of all Americans, in our opinion, believe that the Civil War is still significant today.

<h3>What is a survey?</h3>

A survey is a set of questions used in human subject research with the goal of gathering specific information from a certain population. Surveys can be carried out via the phone, by mail, online, at street corners, and even in shopping centers.

1) The presented data and the notation "n=1507" refer to the random sample of Americans, "X" denoting the proportion of those Americans in the sample who believe that the Civil War is still significant to American politics and political life, and "p cap" denoting the estimated number of those Americans.

Since the problem specifies that majority α=0.05 represents the significance threshold, $p_0$ is the number that we wish to test (no given, but is assumed)

Z would stand for the statistic (interesting variable), and $p_v$ for the p value (variable of interest)

P is the percentage of the public that believes that the Civil War still has an impact on American politics and political life.

2) Useful concepts and formulas

The allegation that more Americans than 50% believe the Civil War is still significant to American politics and political life needs to be tested through a hypothesis (Majority). :

Alternative Hypothesis: p $\geq$ 0.5

Null Hypothesis: p $\leq$ 0.5

The proportion is thought to have a normal distribution.

This test for the percentage of union membership has one tail higher.

Verify whether the sample conforms to the presumptions required for the test to be applied.

a) The random sample must be representative; in this situation, there is no mention of this issue, but it is safe to presume that it exists.

b) The sample size must be sufficient.

$np_0=1507*0.5=753.5 > 10\\n(1-p_0)=1507*(1-0.5)=753.5 > 10$

3. Determine the statistic.

The formula used to calculate the statistic is as follows:

$z=\frac{p-p_0}{\sqrt{\frac{p_0(1-p_0)}{n} } }= \frac{0.56-0.5}{\sqrt{\frac{0.5(1-0.5)}{1507} } }=4.658$

P value= $p_v=P(z > 4.65)=1-P(z < 4.65)=1.581*x*10^{-6}$

According to the alternative hypothesis, the following would be the p value:

P value= $p_v=P(z > 4.65)=1-P(z < 4.65)=1.581*x*10^{-6}$

Using this formula, the confidence interval would be determined.

p ± $z_{\frac{\alpha }{2}}\sqrt{\frac{p(1-p)}{n} }$

With the value of $\alpha$ and $\alpha _2$ , we can get the quantile necessary for the interval in the normal standard distribution for the 90% confidence interval.

$z_{\frac{\alpha }{2} }=2.58$

adding the following to the formula for the confidence interval:

$0.56-2.58\sqrt{\frac{0.56(1-0.56)}{1507} } = 0.527\\0.56+2.58\sqrt{\frac{0.56(1-0.56)}{1507} } = 0.593$

Also provided would be the 90% confidence interval (0.527;0.593).

About 54% to 59% of all Americans, in our opinion, believe that the Civil War is still significant today.

And because the interval does not contain the value of 0.5, we can conclude that, at a 90% level of confidence, the percentage of Americans who believe that the Civil War is still relevant to American politics and political life is higher than 0.5. This result is consistent with the result of part b.

To know more about survey, visit:

brainly.com/question/13192080

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6 0

1 year ago

A) Find a particular solution to y" + 2y = e^3 + x^3. b) Find the general solution.

Reptile [31]

Answer:

a.P.I= $\frac{e^{3x}}{11}+\frac{1}{2}(x^3-3x)$

b.G.S= $C_1Cos \sqrt2 x+C_2 Sin\sqrt2 x+\frac{1}{11}e^{3x}+\frac{1}{2}(x^3-3x}$

Step-by-step explanation:

We are given that a linear differential equation

$y''+2y=e^{3x}+x^3$

We have to find the particular solution

P.I= $\frac{e^{3x}}{D^2+2}+\frac{x^3}{D^2+2}$

P.I= $\frac{e^{3x}}{3^2+2}+\frac{1}{2} x^3(1+\frac{D^2}{2})^{-2}$

P.I= $\frac{e^{3x}}{11}+\frac{1-2\frac{D^2}{4}+3\frac{D^4}{16}+...}{2}x^3$

P.I= $\frac{e^{3x}}{11}+\frac{x^3-2\frac{\cdot3\cdot 2x}{4}}{2}+0}$ (higher order terms can be neglected

P.I= $\frac{e^{3x}}{11}+\frac{1}{2}(x^3-3x)$

b.Characteristics equation

$D^2+2=0$

$D=\pm\sqrt2 i$

C.F= $C_1cos \sqrt2x+C_2 sin\sqrt2 x$

G.S=C.F+P.I

G.S= $C_1Cos \sqrt2 x+C_2 Sin\sqrt2 x+\frac{1}{11}e^{3x}+\frac{1}{2}(x^3-3x)$

3 0

3 years ago

The access code for a car's security system consists of sixsix digits. the first digit cannot be zerozero and the last digit mu

shutvik [7]

There are six digits. The first can be anything but 0. There are 9 other choices.
Are repetitions allowed? Is 999999 permitted.

Repetitions allowed.
9 * 10 * 10 * 10 * 10 * 5 The last digit must be odd.
450,000 <<<< answer.

No repetitions
Sorry this requires more thought.

7 0

3 years ago

A company makes $300 each month selling its products to the public. The company has $435 in its bank account. How many months of

Galina-37 [17]

Answer:

300x = 435, given x represents the amount of months.

So 435 divided by 300 is 1.45 months for that amount.

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers