Is the margin of error equal to two standard deviation?

For example in problem one is the standard deviation .01 because the margin of error is 2%?

And after that do I use the formula and solve for n?

Yup (if the confidence level is 95%).

Yes.

Uh huh.

what about with a 97% confidence level? then its not 2 standard deviations, is it? do u just have to find the z for 97%?
and also how do u find confidence level? basically im having trouble with #2 and #4.

Yup.

I really like these self-answering questions.

how do u find the z tho? i dont remember how to interpolate that direction

Well, the interpolation is done pretty much the same way. You know from the table that z is between 2.1 and 2.2 (closer to 2.2). What percent of the way between .9643 and .9722 is .97? Go that percent of the way between 2.1 and 2.2.

Remember, the margin of error is half of the confidence interval.

The confidence level is related to the z-value (number of standard deviations) through the chart on pg 399.

And the standard deviation is related to the size of the poll through the formulas we discussed in class (assuming p = .5).
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