During the last decade, many institutions dedicated to improving the quality of products and services in the United States have been formed. Many of these groups annually give awards to companies that...

During the last decade, many institutions dedicated to improving the quality of products and services in the United States have been formed. Many of these groups annually give awards to companies that produce high-quality goods and services. An investor believes that publicly traded companies that win awards are likely to outperform companies that do not win such awards. To help determine his return on investment in such companies, he took a random sample of 83 firms that won quality awards the previous year and computed the annual return he would have received had he invested. The investor would like an estimate of the returns he can expect. A 95% confidence level is deemed appropriate.