I need guidance on how to calculate these problems using excel. I used my calculator, but the instructor wants us to use Excel.

A large web retailer is interested inestimating, of all the individuals who visit the web site the proportion who buy a product. They would like this estimate to be within a margin of error+ 0.05 and a confidence level of90%.

1) The sample size that would be necessary to satisfy these requirements is

271

(Enter the answer as aninteger).

2) Using this samplesize, the actual margin of error could be

A. smaller than 0.05.

B. smaller than or equal to 0.05.

C. equal to 0.05.

D. larger than 0.05.

E. larger than or equal to 0.05.