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3 years ago

Free 20 points!! another give away because why not <:

Mathematics

2 answers:

koban [17]3 years ago

7 0

$\huge{\underline{\mathtt{\red{A}\pink{N} \green{S}\blue{W} \purple{E}\orange{R}}}}$

They say oh my god I see the way you shine.....

aleksley [76]3 years ago

6 0

Answer:

thank you soooooo much for the free points

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Is 14/4573 a rational number?

Reika [66]

Yes, once again, The only irrational numbers are the ones with a square root. A rational number is a whole number, a fraction (unless the denominator is 0), a mixed number, or a decimal number. If you had the square root of 4, that would be rational because it can be simplified to 2 or -2. so there for it shall be rational number.

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3 years ago

64 fl oz = _ c Plz answer

vaieri [72.5K]

8oz= 1 cup
So 64oz= 8 cups

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3 years ago

Can someone please answer this for me i cant figure it out.

Jlenok [28]

<h3>Answer:</h3>

$\displaystyle x^{\frac{2}{3}}$

<h3>Step-by-step explanation:</h3>

The rules of exponents tell you ...

... (a^b)(a^c) = a^(b+c) . . . . . . applies inside parentheses

... (a^b)^c = a^(b·c) . . . . . . . . applies to the overall expression

The Order of Operations tells you to evaluate inside parentheses first. Doing that, you have ...

... x^(4/3)·x^(2/3) = x^((4+2)/3) = x^2

Now, you have ...

... (x^2)^(1/3)

and the rule of exponents tells you to multiply the exponents.

... = x^(2·1/3) = x^(2/3)

3 0

3 years ago

Read 2 more answers

-5 = .25d +3 Help me

Natalka [10]

Answer:

$d = - 32$

Step-by-step explanation:

$- 5 = 0.25d + 3 \\ add \: 5 \: from \: both \: sides \\ \\ - 0.25 = 8 \\ divide \: both \: sides \: by \: - 0.25 \\ \\ d = - 32$

7 0

3 years ago

In 2010, the Census Bureau estimated the proportion of all Americans who own their homes to be 0.669. An urban economist wants t

Alexxandr [17]

Answer:

Sample size making use of the Census Bureau: 1,499 American adults.

Sample size without making use of the Census Bureau: 1,692 American adults

ii)

Step-by-step explanation:

The sample size n in Simple Random Sampling is given by

$\bf n=\frac{z^2p(1-p)}{e^2}$

where

z = 1.645 is the critical value for a 90% confidence level (*) 

p= 0.669 is the population proportion given by the Census

e = 0.02 is the margin of error

$\bf n=\frac{(1.645)^2*0.669*0.331}{0.02^2}=1,498.05\approx 1,499$

rounded up to the nearest integer.

(*)This is a point z such that the area under the Normal curve N(0,1) 1nside the interval [-z, z] equals 90% = 0.9

It can be obtained with tables or in Excel or OpenOffice Calc with

NORMSINV(0.95)

If she ignores the Census estimate, the she has to take the largest sample possible that meets the requirements.

Let's show it is obtained when p = 0.5

As we said, the sample size n is

$\bf n=\frac{z^2p(1-p)}{e^2}$

where

e = 0.02 is the error proportion

z = 1.645

hence

$\bf n=\frac{(1.645)^2p(1-p)}{(0.02)^2}=6765.0625p(1-p)=6765.0625p-6765.0625p^2$

taking the derivative with respect to p, we get

n'(p)=6765.0625-2*6765.0625p

and

n'(p) = 0 when p=0.5

By taking the second derivative we see n''(p)<0, so p=0.5 is a maximum of n

This means that if we set p=0.5, we get the maximum sample size for the confidence level required for the proportion error 0.02

Replacing p with 0.5 in the formula for the sample size we get

$\bf n=6765.0625*0.5-6765.0625(0.5)^2=1691.27\approx 1,692$

rounded to the nearest integer.

ii)

When we do not have a proportion but a variable whose approximate standard deviation s is known, then the sample size n in Simple Random Sampling is given by

$\bf n=\frac{z^2s^2}{e^2}$

where

z = 2.241 is the critical value for a 95% confidence level (*) 

s = 7.5 is the estimated population standard deviation

e = 2 hours is the margin of error

$\bf n=\frac{z^2s^2}{e^2}=\frac{(2.241)^2(7.5)^2}{(2)^2}=70.62\approx 71$

(*)This is a point z such that the area under the Normal curve N(0,1) inside the interval [-z, z] equals 95% = 0.95

It can be obtained in Excel or OpenOffice Calc with

NORMSINV(0.9875)

5 0

4 years ago