Dm Statistics Case Study

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DM Statistics Exercise 1: The automobile industry sold 657,000 vehicles in the United States during January 2009 (The Wall Street Journal, February 4, 2009). This volume was down 37% from January 2008 as economic conditions continued to decline. The Big Three U.S. automakers— General Motors, Ford, and Chrysler—sold 280,500 vehicles, down 48% from January 2008. A summary of sales by automobile manufacturer and type of vehicle sold is shown in the following table. Data are in thousands of vehicles. The non-U.S. manufacturers are led by Toyota, Honda, and Nissan. The category Light Truck includes pickup, minivan, SUV, and crossover models. Type of Vehicle Car Light Truck Manufacturer U.S. 87.4 193.1 Non U.S. 228.5 148.0 a. Develop a joint probability table for these data and use the table to answer the…show more content…
Compute the probability of no website visitors in a one-minute period. b. Compute the probability of two or more website visitors in a one-minute period. c. Compute the probability of one or more website visitors in a 30-second period. d. Compute the probability of five or more website visitors in a one-minute period. Exercise 3 : The average stock price for companies making up the S&P 500 is 30$, and the standard deviation is $8.20 (BusinessWeek, Special Annual Issue, Spring 2003). Assume the stock price is normally distributed. a. What is the probability that a company will have a stock price of at least 40$ - Find the z-score of 40. That means 40 is 1.2195 standard deviations above the mean. Having converted 40 to a z-score you find the area to the right of 1.2195 under the standard curve. After that we have to use a Z table or a TI 84 calculator and we find : 0.1113. b. What is the probability a company will have a stock price no higher than $20? Here we are finding the area to the left of -1.2295. Because of symmetry the answer is the same as for

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