According to the National Retail Federation, 34% of taxpayers used computer software to do their taxes for the 2009 tax year. A sample of 125 taxpayers was selected.
a) Calculate the standard error of the proportion.
b) What is the probability that less than 30% of the taxpayers from the sample used computer software to do their taxes?
c) What is the probability that between 28% and 40% of the taxpayers from the sample used computer software to do their taxes?
d) What impact would changing the sample size to 225 taxpayers have on the results of parts a, b, and c?