What is meant by competitive firm?

Miranda Meadow, a Virginia senatorial candidate wants an estimate of the proportion of the population who will support her in the November election. Assume a 95% level of confidence. Meadow wants the estimate to be within 0.04 of the true proportion. Meadow’s political advisors have no estimate available for the proportion that will support her. 

a)How large a sample is required? b)What sampling technique should be used to select such a sample? Explain. c)Past surveys reveal that 10% percent of the voters in Meadow’s state are willing to spend more than $1,000 on a fund raiser dinner. Meadow wants to update this percentage. The new study is to use the 90 percent confidence level. The estimate is to be within 1 percent of the population proportion. What is the necessary sample size?  d)Meadow’s advisors also want to determine the average cost of a 30-second TV ad within the state. What sample size must you take to be 96% confident that the results will be within $75 of the true mean cost per ad given that = $771?