1. The 1990's was a remarkably profitable decade for investors in the U.S. stock market. A sample of individual stocks traded during the calendar years 1993, has been examined for the annual rate of return on investment for each stock. (This rate is defined as the percentage of profit relative to investment.) Assume that the annual rate of return is normally distributed. Sample : 1993 stocks 14 stocks were examined. Sample mean annual rate of return = 6.2% Sample standard deviation of annual rates of return = 3.4% Find a 95% confidence interval for the mean annual rate of return for all U.S. stocks traded during 1993.
2. Scientists from the U.S. Park Service capture baby Pelicans in the Florida Everglades, measure their heights, then release them back to the wild. Assume that Pelicans are captured independently. Suppose that the height of baby Pelicans is normally distributed with a mean height of 12.3 inches and standard deviation of 1.75 inches. What is the probability that one captured baby Pelican has height less than 10 inches?