Please help me in this question

Answer:

A. c = -7

Step-by-step explanation:

Standard form of a quadratic equation is given as ax² + bx + c = 0, where,

a, b, and c are known values not equal to 0,

x is the variable.

Given a quadratic equation of -x² + 4x - 7, therefore,

a = -1

b = 4

c = -7

Answer:

a) 0.6212 = 62.12% probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean.

b) 0.7416 = 74.16% probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean.

c) 0.8804 = 88.04% probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean.

d) None of them ensure, that one which comes closer is a sample size of 100 in option c), to guarantee, we need to keep increasing the sample size.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

The CPA Practice Advisor reports that the mean preparation fee for 2017 federal income tax returns was $273. Use this price as the population mean and assume the population standard deviation of preparation fees is $100.

This means that [tex]\mu = 273, \sigma = 100[/tex]

A) What is the probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean?

Sample of 30 means that [tex]n = 30, s = \frac{100}{\sqrt{30}}[/tex]

The probability is the p-value of Z when X = 273 + 16 = 289 subtracted by the p-value of Z when X = 273 - 16 = 257. So

X = 289

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{289 - 273}{\frac{100}{\sqrt{30}}}[/tex]

[tex]Z = 0.88[/tex]

[tex]Z = 0.88[/tex] has a p-value of 0.8106

X = 257

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{257 - 273}{\frac{100}{\sqrt{30}}}[/tex]

[tex]Z = -0.88[/tex]

[tex]Z = -0.88[/tex] has a p-value of 0.1894

0.8106 - 0.1894 = 0.6212

0.6212 = 62.12% probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean.

B) What is the probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean?

Sample of 30 means that [tex]n = 50, s = \frac{100}{\sqrt{50}}[/tex]

X = 289

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{289 - 273}{\frac{100}{\sqrt{50}}}[/tex]

[tex]Z = 1.13[/tex]

[tex]Z = 1.13[/tex] has a p-value of 0.8708

X = 257

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{257 - 273}{\frac{100}{\sqrt{50}}}[/tex]

[tex]Z = -1.13[/tex]

[tex]Z = -1.13[/tex] has a p-value of 0.1292

0.8708 - 0.1292 = 0.7416

0.7416 = 74.16% probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean.

C) What is the probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean?

Sample of 30 means that [tex]n = 100, s = \frac{100}{\sqrt{100}}[/tex]

X = 289

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{289 - 273}{\frac{100}{\sqrt{100}}}[/tex]

[tex]Z = 1.6[/tex]

[tex]Z = 1.6[/tex] has a p-value of 0.9452

X = 257

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{257 - 273}{\frac{100}{\sqrt{100}}}[/tex]

[tex]Z = -1.6[/tex]

[tex]Z = -1.6[/tex] has a p-value of 0.0648

0.9452 - 0.0648 =

0.8804 = 88.04% probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean.

D) Which, if any of the sample sizes in part (a), (b), and (c) would you recommend to ensure at least a .95 probability that the same mean is withing $16 of the population mean?

None of them ensure, that one which comes closer is a sample size of 100 in option c), to guarantee, we need to keep increasing the sample size.

C is actually 0.8904

for anybody else stuck on this wondering why cengage is telling you c is wrong

Answer:

The correct answer is "1668". A further solution is provided below.

Step-by-step explanation:

According to the question,

Estimated proportion,

[tex]\hat{p} = \frac{574}{1007}[/tex]

  [tex]=0.57[/tex]

Margin of error,

E = 0.02

Level of confidence,

= 90%

= 0.90

Critical value,

[tex]Z_{0.10}=1.65[/tex]

Now,

⇒  [tex]0.02=1.65\times \sqrt{\frac{0.57\times 0.43}{n} }[/tex]

 [tex]0.0004=2.7225\times \frac{0.2451}{n}[/tex]

         [tex]n=\frac{2.7225\times 0.2451}{0.0004}[/tex]

             [tex]=1668.21[/tex]

or,

         [tex]n \simeq 1668[/tex]

Answer:

Step-by-step explanation:

                    Statements                                        Reasons

1). ΔABC with side lengths a, b, c, and h      1). Given

2). Area = [tex]\frac{1}{2}bh[/tex]                                                 2). Triangle area formula

3). [tex]\text{sin}C=\frac{h}{a}[/tex]                                                    3). Definition of sine

4). asin(C) = h                                                4). Multiplication property of

                                                                          equality.

5). Area = [tex]\frac{1}{2}ba\text{sin}C[/tex]                                         5). Substitution property

6). Area = [tex]\frac{1}{2}ab\text{sin}C[/tex]                                         6). Commutative property of

                                                                           multiplication.

Hence, proved.

Answer:

RA = 24

Step-by-step explanation:

Since the triangle is isosceles ( 2 equal sides ) , then LU is a perpendicular bisector , so

AU = RU , that is

4r = 18 - 2r ( add 2r to both sides )

6r = 18 ( divide both sides by 6 )

r = 3

Then

RA = 18 - 2r + 4r = 18 + 2r = 18 + 2(3) = 18 + 6 = 24

Answer:

262.5 miles

Step-by-step explanation:

Correct me if I am wrong

Answer:

0.9984

Step-by-step explanation:

we have shape parameter for the first component as 2.1

characteristics life = 100000

for this component

we have

exp(-2000/100000)².¹

= e^-0.0002705

= 0.9997

for the second component

shape parameter = 1.8

characteristic life = 80000

= exp(-2000/80000)¹.⁸

= e^-0.001307

= 0.9987

the reliability oif the system after 2000  events

= 0.9987 * 0.9997

= 0.9984

Volume of the 3d composite figure is,

(7×6×5)+(7×6×5)/3

= 210+70

= 280 cm³

Relationship between the two volumes,

Volume of the rectangular prism is 3 times the volume of the pyramid.

Answered by GAUTHMATH

Answer:

I was gonna anwer it but somone already did.

Step-by-step explanation:

Answer:

[tex]2\frac{3}{4} +(-4\frac{1}{4} )=-1\frac{2}{4}[/tex]

Step-by-step explanation:

That's the only equation that makes sense to the number line

Answer:

sin²2θ. (cos θ sin θ). cos 2θ

Step-by-step explanation:

finding g'(x)

g'(x)

= 4 (cosθsinθ)³ . { cosθ. (sinθ)' + sinθ. (cosθ)' }

= 4 (cosθsinθ)³ { cosθ. cos θ + sinθ.(-sin θ)}

= 4 (cosθsinθ)³{ cos²θ - sin²θ}

= (4 cosθ sinθ)². (cosθ sinθ). { cos²θ - sin²θ}

= sin²2θ. (cos θ sin θ). cos 2θ

Answer:

b.

Graph B

Step-by-step explanation:

We are given the following linear equation:

[tex]6x = y + 8[/tex]

When x = 0:

[tex]6(0) = y + 8[/tex]

[tex]y = -8[/tex]

Thus, the line goes through (0,-8).

When y = 4:

[tex]6x = y + 8[/tex]

[tex]6x = 4 + 8[/tex]

[tex]6x = 12[/tex]

[tex]x = \frac{12}{6} = 2[/tex]

So also through (2,4).

Thus means that the correct answer is given by Graph B.

Answer:

108 meters with the formula lxhxw

Answer:

-3a+3bx+2ab

Step-by-step explanation:

9514 1404 393

Answer:

  1/3

Step-by-step explanation:

The slope of a line is the ratio of its "rise" to its "run." The "rise" is the change in vertical distance, and the "run" is the corresponding change in horizontal distance between two points on the line. The formula for the slope is ...

  [tex]m=\dfrac{y_2-y_1}{x_2-x_1}\qquad\text{where $(x_1,y_1)$ and $(x_2,y_2)$ are points on the line}[/tex]

In this problem, you are told the line passes through the origin, which is point (x, y) = (0, 0), and through point (6, 2). Using these coordinates in the slope formula gives ...

  [tex]m=\dfrac{2-0}{6-0}=\dfrac{2}{6}=\boxed{\dfrac{1}{3}}[/tex]

__

You may notice that when the line passes through the origin, the slope is simply the ratio y/x of any point on the line. Here, that ratio is 2/6 = 1/3.

_____

Additional comment

A line through the origin is the graph of a proportional relationship. That is, y is proportional to x. The slope of the line is the constant of proportionality. The equation of the line is ...

  y = kx . . . . . . where k is the constant of proportionality.

The line in this problem statement will have the equation ...

  y = (1/3)x

Answer:

1.25. It would be 1.25 if ur just talking about dividing in general which is pretty tough

Answer:

\dfrac54=-4c+\dfrac14 4 5 ​ =−4c+ 4 1 ​ start fraction, 5, divided by, 4, end fraction, equals, minus, 4, c, plus, start fraction, 1, divided by, 4, end fraction

Step-by-step explanation:

Answer:

The absolute change was of -21,665 people.

Step-by-step explanation:

Absolute change:

Final value subtracted by the initial value.

In this question:

Initial value: 699,710

Final value: 678,045

What is the absolute change from 2012 to 2016?

678045 - 699710 = -21,665

The absolute change was of -21,665 people.

Answer:

Approximately [tex]4.75[/tex].

Step-by-step explanation:

Remark: this approach make use of the fact that in the original solution, the concentration of  [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] are equal.

[tex]{\rm CH_3COOH} \rightleftharpoons {\rm CH_3COO^{-}} + {\rm H^{+}}[/tex]

Since [tex]\rm CH_3COONa[/tex] is a salt soluble in water. Once in water, it would readily ionize to give [tex]\rm CH_3COO^{-}[/tex] and [tex]\rm Na^{+}[/tex] ions.

Assume that the [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] ions in this solution did not disintegrate at all. The solution would contain:

[tex]0.3\; \rm L \times 0.2\; \rm mol \cdot L^{-1} = 0.06\; \rm mol[/tex] of [tex]\rm CH_3COOH[/tex], and

[tex]0.06\; \rm mol[/tex] of [tex]\rm CH_3COO^{-}[/tex] from [tex]0.2\; \rm L \times 0.3\; \rm mol \cdot L^{-1} = 0.06\; \rm mol[/tex] of [tex]\rm CH_3COONa[/tex].

Accordingly, the concentration of [tex]\rm CH_3COOH[/tex] and [tex]\rm CH_3COO^{-}[/tex] would be:

[tex]\begin{aligned} & c({\rm CH_3COOH}) \\ &= \frac{n({\rm CH_3COOH})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}[/tex].

[tex]\begin{aligned} & c({\rm CH_3COO^{-}}) \\ &= \frac{n({\rm CH_3COO^{-}})}{V} \\ &= \frac{0.06\; \rm mol}{0.5\; \rm L} = 0.12\; \rm mol \cdot L^{-1} \end{aligned}[/tex].

In other words, in this buffer solution, the initial concentration of the weak acid [tex]\rm CH_3COOH[/tex] is the same as that of its conjugate base, [tex]\rm CH_3COO^{-}[/tex].

Hence, once in equilibrium, the [tex]\rm pH[/tex] of this buffer solution would be the same as the [tex]{\rm pK}_{a}[/tex] of [tex]\rm CH_3COOH[/tex].

Calculate the [tex]{\rm pK}_{a}[/tex] of [tex]\rm CH_3COOH[/tex] from its [tex]{\rm K}_{a}[/tex]:

[tex]\begin{aligned} & {\rm pH}(\text{solution}) \\ &= {\rm pK}_{a} \\ &= -\log_{10}({\rm K}_{a}) \\ &= -\log_{10} (1.76 \times 10^{-5}) \\ &\approx 4.75\end{aligned}[/tex].

Hi there!

[tex]\large\boxed{\frac{dy}{dx} = \frac{1}{2\sqrt{x}}sec^{-1}(\sqrt{x}) + \frac{1}{2|\sqrt{x}|\sqrt{{x} - 1}}}[/tex]

[tex]y = \sqrt{x} * sec^{-1}(-\sqrt{x}})[/tex]

Use the chain rule and multiplication rules to solve:

g(x) * f(x) = f'(x)g(x) + g'(x)f(x)

g(f(x)) = g'(f(x)) * 'f(x))

Thus:

f(x) = √x

g(x) = sec⁻¹ (√x)

[tex]\frac{dy}{dx} = \frac{1}{2\sqrt{x}}sec^{-1}(\sqrt{x}) + \sqrt{x} * \frac{1}{\sqrt{x}\sqrt{\sqrt{x}^{2} - 1}} * \frac{1}{2\sqrt{x}}[/tex]

Simplify:

[tex]\frac{dy}{dx} = \frac{1}{2\sqrt{x}}sec^{-1}(\sqrt{x}) + \sqrt{x} * \frac{1}{2|x|\sqrt{{x} - 1}}[/tex]

[tex]\frac{dy}{dx} = \frac{1}{2\sqrt{x}}sec^{-1}(\sqrt{x}) + \frac{1}{2|\sqrt{x}|\sqrt{{x} - 1}}[/tex]

Answer:

[tex]\displaystyle y' = \frac{arcsec(\sqrt{x})}{2\sqrt{x}} + \frac{1}{2|\sqrt{x}|\sqrt{x - 1}}[/tex]

General Formulas and Concepts:

Algebra I

Calculus

Derivatives

Derivative Notation

Basic Power Rule:

Derivative Rule [Product Rule]:                                                                             [tex]\displaystyle \frac{d}{dx} [f(x)g(x)]=f'(x)g(x) + g'(x)f(x)[/tex]

Derivative Rule [Chain Rule]:                                                                                 [tex]\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)[/tex]

Arctrig Derivative:                                                                                                 [tex]\displaystyle \frac{d}{dx}[arcsec(u)] = \frac{u'}{|u|\sqrt{u^2 - 1}}[/tex]

Step-by-step explanation:

Step 1: Define

Identify

[tex]\displaystyle y = \sqrt{x}sec^{-1}(\sqrt{x})[/tex]

Step 2: Differentiate

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Derivatives

Book: College Calculus 10e

Answer:

6 : 24

Step-by-step explanation:

If we are in the ratio of 1 to 4, the total is 1+4 = 5

Divide 30 by 5

30/5 = 6

Multiply each term in the ratio by 6

1  :4

1*6 : 4*6

6 : 24

Answer:

total ratio:

[tex] = 1 + 4 \\ = 5[/tex]

For the portion of 1:

[tex] = 30 \div \frac{1}{5} \\ = 30 \times 5 \\ = 150[/tex]

For the portion of 4:

[tex] = 30 \div \frac{4}{5} \\ = 30 \times \frac{5}{4} \\ = 37.5[/tex]

= 30 : 7.5

Answer:

150 dollars. if I am wrong correct me

Answer:

C and D

Step-by-step explanation:

15 to 30 galons at $9.95 to $21.00

the minimum amount can be found by calculating the minimum amount sold at a minimum price 15*9.95 = $149.25

the maximum amount can be found by calculating the maximum amount sold at a maximum price 30*21 = $630

there are 2 choices that are between 149.25 and 630, C, and D

Answer:

[tex]A=603.18\ cm^2[/tex]

Step-by-step explanation:

The length of a blade, r = 24 cm

The sweeping angle is 120°.

We need to find the total area cleaned at one sweep of the blade. The area of sector is given by :

[tex]A=\dfrac{\theta}{360}\times \pi r^2[/tex]

[tex]A=\dfrac{120}{360}\times \pi \times 24^2\\\\=603.18\ cm^2[/tex]

So, the total area cleaned at one sweep of the blade is [tex]603.18\ cm^2[/tex].

Answer:

The p-value of the test is 0.0853 > 0.05, which means that there is not enough evidence to reject the manufacturer's claim based on this observation.

Step-by-step explanation:

A manufacturer of nails claims that only 4% of its nails are defective.

At the null hypothesis, we test if the proportion is of 4%, that is:

[tex]H_0: p = 0.04[/tex]

At the alternative hypothesis, we test if the proportion is more than 4%, that is:

[tex]H_a: p > 0.04[/tex]

The test statistic is:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, [tex]\sigma[/tex] is the standard deviation and n is the size of the sample.

4% is tested at the null hypothesis

This means that [tex]\mu = 0.04, \sigma = \sqrt{0.04*0.96}[/tex]

A random sample of 20 nails is selected, and it is found that two of them, 10%, are defective.

This means that [tex]n = 20, X = 0.1[/tex]

Value of the test statistic:

[tex]z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \frac{0.1 - 0.04}{\frac{\sqrt{0.04*0.96}}{\sqrt{20}}}[/tex]

[tex]z = 1.37[/tex]

P-value of the test and decision:

Considering an standard significance level of 0.05.

The p-value of the test is the probability of finding a sample proportion above 0.1, which is 1 subtracted by the p-value of z = 1.37.

Looking at the z-table, z = 1.37 has a p-value of 0.9147

1 - 0.9147 = 0.0853

The p-value of the test is 0.0853 > 0.05, which means that there is not enough evidence to reject the manufacturer's claim based on this observation.

Answer:

Considering an standard significance level of 0.05.

The p-value of the test is the probability of finding a sample proportion above 0.1, which is 1 subtracted by the p-value of z = 1.37.

Looking at the z-table, z = 1.37 has a p-value of 0.9147

1 - 0.9147 = 0.0853

The p-value of the test is 0.0853 > 0.05, which means that there is not enough evidence to reject the manufacturer's claim based on this observation.

Step-by-step explanation:

Answer:

a.) m⁴n²

Step-by-step explanation:

( -m)⁴ × n ²

A negative base raised to an even powers equals a positive.

m ⁴ × n²

multiply the terms

m⁴n²

Answer:

a.) m⁴n²

Step-by-step explanation:

yea

Hi there!  

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I believe your answer is:  

Quadrant III

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Here’s why:  

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Hope this helps you. I apologize if it’s incorrect.  

Answer:

[tex]\displaystyle \frac{d}{dx} = \frac{3x - 5}{2x^\bigg{\frac{3}{2}}}[/tex]

General Formulas and Concepts:

Algebra I

Calculus

Derivatives

Derivative Notation

Derivative Property [Addition/Subtraction]:                                                            [tex]\displaystyle \frac{d}{dx}[f(x) + g(x)] = \frac{d}{dx}[f(x)] + \frac{d}{dx}[g(x)][/tex]

Basic Power Rule:

Derivative Rule [Quotient Rule]:                                                                               [tex]\displaystyle \frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}[/tex]

Step-by-step explanation:

Step 1: Define

Identify

[tex]\displaystyle \frac{3x + 5}{\sqrt{x}}[/tex]

Step 2: Differentiate

Topic: AP Calculus AB/BC (Calculus I/I + II)

Unit: Derivatives

Book: College Calculus 10e

Answer:

n(B) = 1350

Step-by-step explanation:

Using Venn sets, we have that:

[tex]n(A \cup B) = n(A) + n(B) - n(A \cap B)[/tex]

Three values are given in the exercise.

The other is n(B), which we have to find. So

[tex]n(A \cup B) = n(A) + n(B) - n(A \cap B)[/tex]

[tex]2290 = 1300 + n(B) - 360[/tex]

[tex]940 + n(B) = 2290[/tex]

[tex]n(B) = 2290 - 940 = 1350[/tex]

So

n(B) = 1350

Answer:

13.4 cubic feet and 23040 inches

Step-by-step explanation:

Answer:

In cubic feet =  13.3 ft^3 ...........or 13.33ft^3

In cubic inches = 23040in^3

Step-by-step explanation:

In cubic feet it becomes

4(5) = 20 feet ^2   ................but we need volume in feet

so 8 inches = .............2/3 of a foot = 0.666667

Answer therefore is   (4) x (5) x (0.666667) = 13.32ft^3

In cubic inches it becomes

4 x 12 = 48 inches

5  x 12  = 60 inches

and 8 inches

48 x 60 x 8 = 23040 in^3

We check by squaring the divider

23040/12^3 = 13.333

We only square and square again to find a cube but to square once we do this with area too.

Area 1. =  4 x 5 = 20 feet^2

Area 2. =  48 x 60 = 2880 in ^2  / 12^2 = 20