Thomson Financial, statistics homework help

Question 38 on P369 (Numbers are different from the textbook question)According to Thomson Financial, through January 25, 2006, the majority of companies reported profits had beaten estimates (BusinessWeek, February 6, 2006). A sample of 160 companies showed 100 beat estimates, 30 matched estimates, and 30 fell short.a. What is the point estimate of the proportion that fell short of estimates? Answer:b. Determine the margin of error and provide a 90 percent confidence interval for the proportion that beat estimates.Answer: c. Refer to question b, how large a sample is needed if the desired margin of error is 0.05?Answer: