A study was conducted in order to estimate ?, the mean number of weekly hours that U.S. adults use computers at home. Suppose a random sample of 81 U.S. adults gives a mean weekly computer usage time of 8.5 hours and that from prior studies, the population standard deviation is assumed to be ? = 3.6 hours.
A similar study conducted a year earlier estimated that ?, the mean number of weekly hours that U.S. adults use computers at home, was 8 hours. We would like to test (at the usual significance level of 5%) whether the current study provides significant evidence that this mean has changed since the previous year.
Using a 95% confidence interval of (7.7, 9.3), our conclusion is that:
a. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
b. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls outside the confidence interval.
c. the current study does provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
d. the current study does not provide significant evidence that the mean number of weekly hours has changed over the past year, since 8 falls inside the confidence interval.
e. None of the above. The only way to reach a conclusion is by finding the p-value of the test.

Answer:

[tex]12 \sqrt{6} [/tex]

Step-by-step explanation:

[tex]2 \sqrt{3} \times 3 \sqrt{8} \\ (2 \times 3) \sqrt{(3 \times 8)} \\ 6 \sqrt{24} \\( 6 \times 2) \sqrt{6 } \\ 12 \sqrt{6} [/tex]

Answer:

im not sure but i think the answer is C) y = 2(x - 6)^2 + 5

The equation models the same quadratic relationship as function f(x) = 2x^2 - 12x + 11 will be 2(x-3)²-7.Option B is correct.

An equation is a statement that two expressions, which include variables and/or numbers, are equal. In essence, equations are questions, and efforts to systematically find solutions to these questions have been the driving forces behind the creation of mathematics.

It is given that, the function is,

f(x) = 2x^2 - 12x + 11

We have to find the equation models the same quadratic relationship as the given function,

⇒2x²-12x+11

Take common 2 in the complete equation,

⇒2(x²-6x+11/2)

Add and subtract 9 from the complete equation,

⇒2(x²-6x+9-9+11/2)

Rearrange the equation as,

⇒2[(x-3)²-(7/2)]

⇒2(x-3)²-7

Thus, the equation models the same quadratic relationship as function f(x) = 2x^2 - 12x + 11 will be 2(x-3)²-7.Option B is correct.

Learn more about the equation here,

https://brainly.com/question/10413253

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Answer: -8

Step-by-step explanation: So we after simplification we get

[(2/5) - (1/2) + (3/5)+ (7/2)] - [(3/5)/(1/4) - (1/5)]

After this I suppose it's just addition & subtraction, and can be easily done to get -8.

Answer:

[tex]\pm 9in^2[/tex]

Step-by-step explanation:

We are given that

Radius of end of a log, r= 9 in

Error, [tex]\Delta r=\pm 1/2[/tex]in

We have to find the error in computing the area of the end of the log by using differential.

Area of end of the log, A=[tex]pi r^2[/tex]

[tex]\frac{dA}{dr}=2\pi r[/tex]

[tex]\frac{dA}{dr}=2\pi (9)=18\pi in^2[/tex]

Now,

Approximate error in area

[tex]dA=\frac{dA}{dr}(\Delta r)[/tex]

Using the values

[tex]dA=18\pi (\pm 1/2)[/tex]

[tex]\Delta A\approx dA=\pm 9in^2[/tex]

Hence, the possible propagated error in computing the area of the end of the log[tex]=\pm 9in^2[/tex]

Answer:

[tex]A = (254.34 \pm 28.26) in^2[/tex]

Step-by-step explanation:

radius, r = 9 inches

error = 0.5 inch

The area of the end is

A = 3.14 x r x r = 3.14 x 9 x 9 = 254.34 in^2

[tex]A = \pi r^2\\\\\frac{dA}{dr}=2\pi r\\dA = 2 pi r dr \\\\dA = 2 \times 3.14\times 9\times 0.5 = 28.26[/tex]

So, the area is given by

[tex]A = (254.34 \pm 28.26) in^2[/tex]

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Explanation:

Consider a very small town of only 4 people.

If 1 person bikes to work, then 1/4 = 0.25 = 25% of the population commutes by bicycle. We see that the remaining 4-1 = 3 people don't travel by bike.

The odds against selecting someone who uses their bike to get to work is 3:1 which is why the answer is choice B

We list the number of people we don't want first, and then the number of people we do want (those who use a bike). A colon separates the two values to form the odds ratio.

We can say "3:1" as "3 to 1". It means we're 3 times more likely to select someone we don't want vs someone we do want. The odds are against the bike person which is why the value we don't want is listed first.

In contrast, if your teacher asked "what are the odds in favor of selecting someone who commutes by bicycle?" then the answer would be 1:3. We simply swap the positions of what we set up earlier.

Answer:

B i think

Step-by-step explanation:

Answer:

CD=20

Step-by-step explanation:

Use the pythagorean theorem: a²+b²=c²

(20√2)²-20²=a²

400(2)-400

800-400=400

√400=20

[tex]You can call c the number of children and a for adults; you get:5.20c+8.50a=1097.60anda=4c meaning that the number of adults was four times the children.Substituting this value of a into the first equation we get:5.2c+8.5(4c)=1097.65.2c+34c=1097.6rearranging:c=1097.639.2=28and so:a=4c=4⋅28=112[/tex]

I got:  28  children and  112  adults.

Answer:

The solutions are x = -4 and x = 4.

Step-by-step explanation:

Solving a quadratic equation:

We have to find x for which [tex]y = 0[/tex].

In this question:

[tex]y = 16 - x^2[/tex]

So

[tex]16 - x^2 = 0[/tex]

[tex]x^2 = 16[/tex]

[tex]x = \pm \sqrt{16}[/tex]

[tex]x = \pm 4[/tex]

The solutions are x = -4 and x = 4.

Answer:

Its the first one

Answer:

6ab

Step-by-step explanation:

Answer:

The sale price was 60% of the purchase price.

Step-by-step explanation:

Given that Blake bought a motorcycle for $ 550 last year and sold it for $ 330 this year, to determine what is his sale price as a percentage of his purchase price, the following calculation must be performed:

550 = 100

330 = X

330 x 100/550 = X

33000/550 = X

60 = X

Therefore, the sale price was 60% of the purchase price.

Answer:

32year

Step-by-step explanation:

let Ahmed be x years then sheriff will be x+8

in 7years time

sheriff will be x+8+7=x+15

Then Ahmed will be x+7

sum of their ages will be 7\10×100=70years

x+15+x+7=70

collect like terms

2x+22=70

2x=70-22

2x/2=48/2

x=24years

Sheriff=24+8

32years

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Answer:

  3 3/8 inches

Step-by-step explanation:

If you spend a little time looking at the marks on the ruler, you see that the smallest marks divide each inch into 8 parts. The ribbon comes to the 3rd small mark* after the 3-inch mark, so the length of the ribbon is 3 3/8 inches.

_____

* Technically, it is the second small mark, as the marks are small, medium, small. It marks the end of the third space, where each space is 1/8 inch.

Answer:

-2/5 (3x-10z)

Step-by-step explanation:

Answer:

3.39794000867

Step-by-step explanation:

first add log 125 and 625 and divide the answer by log 25 and minus the answer by 5

Answer:

The answer is 7.

the first one is a quadrilateral

Step-by-step explanation:

a quadrilateral have four side

[tex]v = k {r}^{3} [/tex]

[tex]562.54 = k \times {7.5}^{3} [/tex]

[tex]562.54 = 421.88k[/tex]

[tex]k = 562.54 \div 421.88[/tex]

[tex]k = 1.33[/tex]

since

[tex]v = k {r}^{3} [/tex]

[tex]v = 1.33 \times {9}^{3} [/tex]

[tex]v = 729 \times 1.33[/tex]

[tex]v = 969.57[/tex]

Answer:

C: [tex]\frac{7x}{4} + 5y[/tex]

Step-by-step explanation:

1. Realize that 12 inches is 1 feet and 36 inches is 1 yard.

2. Multiply it so that both are inches.

[tex]\frac{5y}{12} * 12 = 5y[/tex]

[tex]\frac{7x}{144} * 36 = \frac{7x}{4}[/tex]

3. Add together [tex]\frac{7x}{4} + 5y[/tex]

Answer:

C.

Step-by-step explanation:

I also recommend to just search these things on the internet. it would be much faster.

1 ft = 12 in

1 yd = 3 ft = 3×12 = 36 in

so, we need to multiply a given number of ft by 12, and a given number of yards by 36 to get the inches.

5y/12 × 12 = 5y

7x/144 × 36 = 7x/4

that is all there is to it.

Answer:

[tex]a = \frac{dv}{dt } = \frac{20 - 0}{2} = 10[/tex]

Answer:12

Step-by-step explanation:

Square root of 16x9=12

Answer:

Step-by-step explanation:

When the height of the rightangle is drawn to the hypotenuse, the hypotenuse is divided into two parts that when multiiplied = the square of the height.

x^2 (the height) = 16 * 9

x^2 = 144                  Take the square root of both sides

sqrt(x^2) = sqrt(144)

x = 12

Answer: Choice D. 3 : r=3

Step-by-step explanation:

Easiest method and probably only method given the graph without knowing exact points besides an asymptote at x=-3.

Since we know there is an asymptote at x=-3, we just solve for the denominator and find r, when x=-3.

We are setting equation equal to 0, because when the denominator is 0, the graph has an asymptote at that point.

x+r=0

-3+r=0

r=3

Answer:

r=3

Step-by-step explanation:

Given:

The expression is:

[tex]4\log_{\frac{1}{2}}w+(2\log_{\frac{1}{2}}u-3\log_{\frac{1}{2}}v)[/tex]

To find:

The single logarithm for the given expression.

Solution:

We have,

[tex]4\log_{\frac{1}{2}}w+(2\log_{\frac{1}{2}}u-3\log_{\frac{1}{2}}v)[/tex]

It can be written as:

[tex]=\log_{\frac{1}{2}}w^4+(\log_{\frac{1}{2}}u^2-\log_{\frac{1}{2}}v^3)[/tex]       [tex][\because \log a^b=b\log a][/tex]

[tex]=\log_{\frac{1}{2}}w^4+\log_{\frac{1}{2}}\dfrac{u^2}{v^3}[/tex]       [tex][\because \log \dfrac{a}{b}=\log a-\log b][/tex]

[tex]=\log_{\frac{1}{2}}\left(w^4\times \dfrac{u^2}{v^3}\right)[/tex]      [tex][\because \log ab=\log a+\log b][/tex]

[tex]=\log_{\frac{1}{2}}\dfrac{w^4u^2}{v^3}[/tex]

Therefore, the correct option is B.

Answer:

The answer is B :))

Step-by-step explanation:

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Answer:

  7.0 cm

Step-by-step explanation:

The relationship between radius and area of a sphere is ...

  A = 4πr²

Then the radius as a function of area is ...

  r = √(A/(4π)) = (√(A/π))/2

For an area of 616 cm², the corresponding radius is ...

  r = (√(616/π))/2 ≈ 7.0 cm . . . . radius of the orange

Hope you could understand.

If you have any query, feel free to ask.

Answer:

The correct answer is A. 9.4 inches.

Step-by-step explanation:

Given that the volume of a boys' basketball is 434 cubic inches, and Dan would like to get a ball with half the volume for his son, to determine what is the diameter of the ball that Dan will buy for his son, the following calculation has to be done, knowing that the volume of a sphere is four thirds multiplied by pi multiplied by the radius cubed:

4/3 x 3.14 x X ^ 3 = 434

4.186 x X ^ 3 = 434

X ^ 3 = 434 / 4.186

X = 3√ 103.662

X = 4.7

In turn, since the radius of a sphere is equal to half its diameter, the diameter of the basketball is 9.4 inches (4.7 x 2).

Answer:

429 & 431

Step-by-step explanation:

Consecutive numbers are numbers that come right after the other.

Let x = first room number

[tex]x+x+2=860\\2x+2=860\\2x=858\\x=429\\\\(429) + 2 = 431[/tex]

Therefore, the two room numbers are 429 and 431.

Answer:

c

Step-by-step explanation:

that is the procedure above