Margin of Error-- poll problem![PLEASE HELP BEFORE TOMORROW]

[megan0430]

Here is the original question.

Suppose a pollster wnats to poll 500 people and wants a 99% confidence level, calculate the margin of error.

I know that margin of error equals z-score times standard of deviation. But I have no idea how to get those with only this information. please help! i have math finals tomorrow!

 

[galactus]

It doesn't appear there's enough information. You need the standard deviation. One rough way to estimate the standard deviation is the range divided by 4.

You could use \(\displaystyle 2.575\frac{125}{\sqrt{500}}=14.39\)

That's rough, though.

If it's proportions and no initial estimate is given, use p=0.5 and q=0.5