7. The National Fire Protection Association reported that house fires in the United States result in $6.8 billion in losses annually (National Fire Protection Association, September 2015). Suppose a random sample of 50 house fires in San Antonio yields a mean loss of $18,503. If the population standard deviation iss = $3,300, what is the margin of error for a 95% confidence interval? What would you recommend if the study required a margin of error of $300 or less?