This practice exam is similar in difficulty to the actual in-class portion of the midterm. You will additionally have a take-home portion of your exam that will lean toward essay-style questions and count for 30% of your midterm. Note that I do not guarantee that all types of problems on the midterm are represented here, nor do I guarantee that all content tested on the midterm is represented here. 1. Sign on San Diego, a service of the San Diego Union Tribune contains many advertisements for used vehicles. A simple random sample of 27 ads for used SUV’s, model years 19902004 was taken from the set of 234 ads. A sample ad, as well as a table giving the manufacturer, model year, and asking price for vehicles in the sample is given below.
Year 2003 Make/Model Chevrolet Tahoe Price $23,500 Mileage 43,935 Seller Private Seller
This one is the best one you will ever see. Well Taken care of. LT Preferred Equipment Group, 5.3L Vortec Motor, Fully Loaded with XM Radio, Running Boards, Home Link, 6 way power
Year 2004 2001 2002 2004 2003 2004 2003 2004 2003 2003 2004 2002 2003 2004 2004 2001 2000 2003 1997 2002 2002 2002 2002 2004 2001 2004 2000 Make Toyota BMW Chevrolet GMC Toyota Volvo Ford Ford Mercedes Chevrolet Jeep Ford Chevrolet Toyota Jeep Ford Mitsubishi Chevrolet Jeep BMW Toyota Ford Ford Chevrolet Mitsubishi Volvo Kia Mean Standard Deviation Asking Price 26,815 26,900 17,797 26,995 23,900 30,995 17,598 No Price 22,900 18,990 13,995 10,000 21,975 22,988 15,995 18,990 7,600 No Price 5,800 28,900 17,995 15,995 15,605 21,990 9,988 31,995 5,990 19,148 7,542
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a. Form a 95% confidence interval for the mean price at which a used SUV is advertised.
b. Treat these listings as a pilot study. Based on these data, how many advertisements would you need to sample in order to have a margin of error of $500 for estimation of the mean advertised price of a van with a 95% confidence interval?
c. What variable could prove useful in