what is the minimum sample size needed for a confidence interval of getting head in tossing a coin with no more than a 2% margin of error?

Question

I'm not sure what equation to use or how to do it. I know we are looking for the sample size. The answer is 2401 but can someone show me the work that goes into it. I would really appreciate it.

Answer 1

phat - Error < p < phat + Error

 

The Error comes from the formula E=z_c*sqrt[p(1-p)/n].  If you do some algebra, you will get 

 

p(1-p)* z_c²    = n.  You will probably need to round up the n.

             E²

 

Can you take it from here?