The Tyco Video Game Corporation finds that it is losing income because of slugs used in its video games. The machines must be adjusted to accept coins only if they fall within set limits. In order to set those limits, the mean wight of quarters in circulation must be estimated. A sample of quarters will be weighed in order to determine the mean. How many quarters must we randomly select and weigh if we wan to be 95% confident that the sample mean is within 0.035 g of the true population mean for all quarters? Based on results from a sample of quarters, we can estimate the population standard deviation as 0.068 g.