A survey was conducated of 610 office workers to determine telephone answering practices i.e. how many were able to answer incoming calls and how many calls went to voicemail. A total of 280 office workers indicated that they never need voice mail and are able to take every call.

A. What is the point estimate of the proportion id the population of office workers who were able to take every call?

B. At 90% confidnence what is the margin of error?

C. What is the 90% confidence interval of the proportion of the population of workers who are able to take every phone call?