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alexgriva [62]
3 years ago
14

A researcher wants to estimate the percentage of all adults that have used the Internet to seek pre-purchase information in the

past 30 days, with an allowable sampling error (E) of 0.03 and a confidence level of 99.74%. Of secondary data indicated that 25% of all adults had used the Internet for such a purpose, what is the sample size
Mathematics
1 answer:
lara31 [8.8K]3 years ago
7 0

Answer:

The sample size is 1875.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the zscore that has a pvalue of 1 - \frac{\alpha}{2}.

The margin of error is:

M = z\sqrt{\frac{\pi(1-\pi)}{n}}

Sampling error of 0.03.

This means that M = 0.03

99.74% confidence level

So \alpha = 0.0026, z is the value of Z that has a pvalue of 1 - \frac{0.0026}{2} = 0.9987, so Z = 3.

25% of all adults had used the Internet for such a purpose

This means that \pi = 0.25

What is the sample size

The sample size is n. So

M = z\sqrt{\frac{\pi(1-\pi)}{n}}

0.03 = 3\sqrt{\frac{0.25*0.75}{n}}

0.03\sqrt{n} = 3\sqrt{0.25*0.75}

Simplifying by 0.03 both sides

\sqrt{n} = 100\sqrt{0.25*0.75}

(\sqrt{n})^2 = (100\sqrt{0.25*0.75})^2

n = 1875

The sample size is 1875.

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238 +439 round you're answer to the. earest dollar​
Paha777 [63]

Answer:

677

Step-by-step explanation:

238 + 439 = 677

It is t possible to round it form the ones (dollar) place.

8 0
3 years ago
Kasey and her sister both sold cookie dough. Her sister sold three times as many tubs of cookie dough. If they sold a total of 8
Rufina [12.5K]
X= number of tubs Kasey sold
3x= number tubs sister sold

Add the number sold by Kasey and her sister to equal the total sold (88).

x + 3x= 88
combine like terms

4x= 88
divide both sides by 4

x= 22 number tubs Kasey sold


Number Sold by Sister
3x= 3(22)= 66


CHECK:
x + 3x= 88
22 + 3(22)= 88
22 + 66= 88
88= 88


ANSWER: Kasey sold 22 tubs and her sister sold 66 tubs.

Hope this helps! :)
7 0
3 years ago
2) Find the area without graphing. A(25, 30), B (-15, 30), C(-15, 22), D(25, 22) What is this shape?
Katen [24]

Answer:

The answer to the question is a rectangle.

Step-by-step explanation:

6 0
2 years ago
Toby began making a grilled cheese sandwich at 1:48 P.M. The sandwich was ready at
Doss [256]

Answer:

5 minutes he took to grill the sandwich

7 0
3 years ago
Read 2 more answers
F(x)=3x-8
iVinArrow [24]
What this is asking is for you to plug values into the following function:f(x)=\frac{3x-8}{6x}

Since the question is asking you to find f(3)-f(1), this is how you work it out:
You take the function;
f(x)=\frac{3x-8}{6x}
And plug the numbers indicated in for x;
f(x)=\frac{3x-8}{6x}\\
f(3)=\frac{3(3)-8}{6(3)}\\
f(3)=\frac{9-8}{18}\\
f(3)=\frac{1}{18}\\\\
f(1)=\frac{3(1)-8}{6(1)}\\
f(1)=\frac{3-8}{6}\\
f(1)=\frac{-5}{6}\\\\
Now\ what\ you\ do\ is\ you\ subract\ f(3)\ and\ f(1).\\
f(3)-f(1)\\
f(3)-f(1)=\frac{1}{18}-\frac{-5}{6}\\
f(3)-f(1)=\frac{1}{18}-\frac{-15}{18}\\
f(3)-f(1)=\frac{1+15}{18}\\
f(3)-f(1)=\frac{16}{18}=\frac{8}{9}
So the answer to f(3) - f(1) = \frac{8}{9}
6 0
2 years ago
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