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first 2 weeks. 50 people who joined the programme are sampled, their weight loss is 9 pounds with a standard deviation of 2.8 pounds. Can we conclude at the .05 level that a person joining the programme will lose less than 10 pounds? (2) The following is a random sample of 90-day futures prices in dollars for 1 troy oz. of silver from The Wall Street Journal issues in May and June of 1997: 4.74, 4.77, 4.87, 4.91, 4.83, 4.72, 4.92, 4.86, 4.97, 4.71, 4.90, 4.93, 4.75, 4.88, 4.79, 4.83, 4.89. Required: a. Calculate the mean b. Median c. Standard deviation of the 90-day future price of silver data (3) A mining company needs to estimate the average amount of copper ore per ton mined. A random sample of 50 tons gives a sample mean of 146,75 pounds. The population standard deviation is assumed to be 35.2 pounds. Required: a. Give a 95% confidence interval for the average amount of copper in the population of tons mined. b. Give a 90% confidence interval for the average amount of coper per ton c. Give a 99% confidence interval for the average amount of coper per ton (4) An e-commerce Website gets 2,385 visitors on a particular day. Among these, 1790 visitors explore the products by looking at more pages at the site. Among these 1790 visitors who explore the products, 387 make a purchase. Required: a. If a visitor chosen at random from all those who visited the site, what is the probability that the visitor explored the products b. If a visitor is chosen at random from all those who visited the site, what is the probability that the visitor made a purchase. c. If a visitor is chosen at random from all those who explored the products, what is the probability that the visitor made a purchase. d. Which of the preceding three probabilities is relevant to the design of the home page that leads to product page.