Question

In a random sample of 50 undergraduate students at a college, it was found that 44 students regularly access social networking websites from their college library. What is the margin of error for the true proportion of all undergraduates who access social networking sites from their college library?

Answer 1

margins of error tend to have a confidence interval associated with them

Answer 2

you will need to know the sample propotion, and its complement; as well as the sample size

Answer 3

that many students don't know the process of expiration dates

Answer 4

if we assume a test statistic of 1 .. then the margin of error can be calculated as:\[\sqrt{\frac{x(n-x)}{n^3}}\]

Answer 5

I have not the slightest a' clue as to how to approach this, I've never even seen the equation you've written down. If you could somehow manage to explain to me how I can solve this that would be great. @amistre64 @aggie12341

Answer 6

I've tried plugging in 50 and 44 into the equation. x=50, n=44. Then I flipped them; n=50, x=44, and I still didn't get my answer that was listed.

Answer 7

from the equation to find a z score:

\[z=\frac{x-\bar x}{s/\sqrt n}\]
\[z\frac{s}{\sqrt n} =x-\bar x\]
\[\bar x+ z\frac{s}{\sqrt n} =x\]
this is the approach to a confidence interval with a margin of error of that z part

Answer 8

it can be shown that \(\large s = \sqrt{\frac xn~\frac{n-x}{n}}\)

Answer 9

what are the options you have?

Answer 10

1.)0.046
2.)0.038
3.)0.014
4.)0.070
5.)0.092

Answer 11

i get one of them ... what results did you get when you plugged in for: x = 44, n = 50

Answer 12

-0.00049805605361561856057535055557723213698687730396915432704...

Answer 13

http://www.wolframalpha.com/input/?i=sqrt%2844%2850-44%29%2F50%5E3%29

you must be entering it in wrong .. or hitting the wrong buttons

Answer 14

I've tried using wolframalpha, it won't allow all the numbers to go under the square root.

Answer 15

you have to use your paranthesis correctly

sqrt()

sqrt(44(50-44)/50^3)

works fine

Answer 16

It was using sqrt 50 * the rest of the equation.

Answer 17

Oh, that might have been the mistake, thank you.

Answer 18

good luck :)