It is estimated that the proportion of union members in favor of the new contractis between 0.3and 0.5.The sponsors of the proposition would like to survey union members and get a 95 percent confidence interval for the true proportion of people in favor of the new contract. They want to restrict the error level to 5 percentage points (5%). Given the likelihood of the survey being delivered to a union member is 0.7(incidence rate), and the response rate is 0.5, how many surveys should they send out? Please show your calculation.