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BlackZzzverrR [31]

3 years ago

7

To determine whether voters would be willing to vote for a tax increase to improve the city's schools, the board of education su

rveys 500 parents of children in the city's schools.
Why is this sample likely to be biased?

A.
The entire population of the city was not surveyed.

B.
Parents of school children are too busy to be bothered with surveys.

C.
There are not enough people in the sample.

D.
Parents of school children are more likely to be willing to pay more to improve schools. A ?

1 answer:

Vladimir [108]3 years ago

6 0

No, its d because the more likely teachers/parents of school kids they will have to be paying more

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The perimeter of GHJ

Dafna1 [17]

They have a scale factor of 5:6 so first we need to find the perimeter of KLM:
$11 + 14 + 17 = 42$
Then apply the scale factor of 5:6:
$\frac{5}{6} = \frac{x}{42}$
Set the denominators equal:
$\frac{35}{42} = \frac{x}{42}$
So we see that the perimeter of GHJ is 35.

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3 years ago

Find the number that makes the ratio equivalent to 2:6.<br><br> 8:

Citrus2011 [14]

A ratio is used to describe how two or more quantities are related. For example, we might say that a fruit drink calls for sugar crystals to be mixed with water in a ratio of 2:6. This means that for every 2 scoops sugar crystals, there will need to be 6 ounces of water. If there were 200 scoops of sugar crystals, there would need to be 600 ounces of water.

4 0

3 years ago

The circumference of a sphere was measured to be 80 cm with a possible error of 0.5 cm. A) Use differentials to estimate the max

siniylev [52]

Answer:

A) The maximum error in the calculated surface area: $25cm^2$

Relative error: $0.013$

B) The maximum error in the calculated volume: $162cm^2$

Relative error: $0.019$

Step-by-step explanation:

A) The formula for the surface area is:

$A=4\pi r^2$

The measured value is the circumference which is equal to:

$C=2\pi r$

then the radius is:

$r=\frac{C}{2\pi}$

Substituting in the formula of the surface:

$A=4\pi(\frac{C}{2\pi})^2\\A=4\pi(\frac{C^2}{4\pi^2})\\A=\frac{C^2}{\pi}$

Using the formula to calculate the error:

$dy=f'(x)dx$

Where $x$ is the variable measured and $y$ is a function of $x$ ( $y=f(x)$ ).

$dA=f'(C)dC\\dA=\frac{2C^{(2-1)}}{\pi}dC\\dA=\frac{2C}{\pi}dC$

We have C=80cm and dC=0.5cm

$dA=\frac{2C}{\pi}dC\\dA=\frac{2(80)}{\pi}(0.5)\\dA=\frac{160}{\pi}(0.5)\\dA=50.9296(0.5)\\dA=25.4648\approx25cm^2$

The relative error is the maximum error divide by the total area. The total area is: $A=\frac{C^2}{\pi}=\frac{(80)^2}{\pi}=\frac{6400}{\pi}=2037.1833cm^2$

$\frac{dA}{A}=\frac{25.4648}{2037.1833} =0.0125\approx0.013$

B) The formula for the volume is:

$V=\frac{4}{3} \pi r^3$

Using $r=\frac{C}{2\pi}$

$V=\frac{4}{3} \pi r^3\\V=\frac{4}{3} \pi (\frac{C}{2\pi})^3\\V=\frac{4}{3} \pi (\frac{C^3}{8\pi^3})\\V=\frac{1}{3}(\frac{C^3}{2\pi^2})\\V=\frac{C^3}{6\pi^2}$

The maximum error is:

$dV=\frac{3C^{3-1}}{6\pi^2}dC\\dV=\frac{C^{2}}{2\pi^2}dC\\dV=\frac{(80)^{2}}{2\pi^2}(0.5)\\dV=\frac{6400}{2\pi^2}(0.5)\\dV=\frac{6400}{2\pi^2}(0.5)\\dV=(324.2278)(0.5)\\dV=162.1139\approx162cm^2$

The calculated volume is:

$V=\frac{C^3}{6\pi^2}\\V=\frac{(80)^3}{6\pi^2}\\V=\frac{512000}{6\pi^2}\\V=8646.0743$

The relative error is:

$\frac{dV}{V}=\frac{162.1139}{8646.0743}=0.0188\approx0.019$

3 0

2 years ago

What is the value of f(-4)

maria [59]

(-4) is the same as x, so looking the conditions that are the results for the function, you realize:

-2 is the result of the function to the values of X that are under -3: the result will be -2 if x < -3

x < -3 ; x = -4 ; -4 < -3 (it's true), in other words, -4 is less than -3, so f(-4) = -2

8 0

3 years ago

If the diameter is 15.5 cm what is the circumference

tresset_1 [31]

Answer:

see below

Step-by-step explanation:

The circumference is given by

C = pi *d

C = 15.5 pi

If we approximate pi by 3.14

C = 15.5 * 3.14

C =48.67

If we use the pi button

C =48.69486813

8 0

3 years ago