In a survey conducted with 600 participants across the United States, 450 were found to have studied science in college. If we were to predict the population proportion with a 99.7% confidence, what would the confidence interval be?

69.7% to 80.3%
73.23% to 76.76%
71.46% to 78.53%
73.5% to 76.5%

Question

In a survey conducted with 600 participants across the United States, 450 were found to have studied science in college. If we were to predict the population proportion with a 99.7% confidence, what would the confidence interval be?

69.7% to 80.3%
73.23% to 76.76%
71.46% to 78.53%
73.5% to 76.5%

anonymous · Answer

I have the steps to this problem but I went wrong somewhere so I don't understand it

dan815 · Answer

okay, so first 450/600 = ?

anonymous · Answer

0.75

dan815 · Answer

okay now for a 99.7 %, u have to find the Z score for that

dan815 · Answer

the next step is to find out what the standard deviation of thing should be

anonymous · Answer

ohhh see, that was the step I was missing, the standard deviation. Except idk how to do it

dan815 · Answer

oh um also we know the center is definately 0.75 right

anonymous · Answer

yes..

dan815 · Answer

or 75%, some of the choices u are given arent centered around that, so they can eliminated rightway

anonymous · Answer

would it be D?

dan815 · Answer

nvm, all them are centered around 75%  cant elimnate any argh

anonymous · Answer

oh okay so what do I do now

dan815 · Answer

C is definitely wrong 
71.46% to 78.53%
as it should say  71.46% to 78.54%

anonymous · Answer

Well I wrote all the answers correctly so idk, I just checked

dan815 · Answer

its probably just bad rounding

anonymous · Answer

So it's definitely not C?

dan815 · Answer

What is the Z score u foundÉ

anonymous · Answer

the formula for z score is $$z= \frac{ X-\mu }{ \sigma }$$ 

right...

dan815 · Answer

yes thats another one,. but we cant use that right now

anonymous · Answer

oh... then what do we use

dan815 · Answer

i just mean we have to find Z score, for the 99.7 %

dan815 · Answer

you have to look at that table and chart

anonymous · Answer

okay how do I do that

anonymous · Answer

http://www.statisticshowto.com/tables/t-distribution-table/ this one right

anonymous · Answer

cause this is where I was stuck, I wasn't sure what numbers or whatever to look at on the chart

dan815 · Answer

click on the 2 tail one

dan815 · Answer

https://www.youtube.com/watch?v=_x6j-rH33Og you can watch this, i know it says typically not used for sample size greater than 30.. but the standard deviation is unknown so, what else can we do

anonymous · Answer

wait is it B?

dan815 · Answer

no clue it looks like info is missing, what can we do with sample deviation is unknown and the pop deviation is unknown @hartnn

anonymous · Answer

here is the entire question

dan815 · Answer

ya hm not sure

anonymous · Answer

ok I just need help cause I need to answer it soon

dan815 · Answer

@ganeshie8 is the question missing info??

anonymous · Answer

so do you know anything..

anonymous · Answer

@ParthKohli

ganeshie8 · Answer

I am eating at the moment but I found this https://answers.yahoo.com/question/index?qid=20140522184044AAlIk3W

anonymous · Answer

I'm on my school computer so yahoo is blocked, could you tell me what it says

ganeshie8 · Answer

how about this http://gyazo.com/d103059ce0cd9eadfd631e125a3f3bc9

anonymous · Answer

no it's still blocked..

ganeshie8 · Answer

try this

anonymous · Answer

thanks so much :)

ganeshie8 · Answer

np