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Unformatted text preview: Test 2  Statistics 211506 (Spring 2007) Name: Student ID: • This test consists of 5 numbered pages. Make sure you have all 5 pages. It is your responsibility to inform me if a page is missing!!! • You have 70 minutes to complete this test. • You may use the provided crib sheets, all appropriate tables and a calculator. • If I provide partial results—assume they are correct and use them even if they are not. • If there is no correct answer or if multiple answers are correct, select the best answer. • There is no penalty to wrong answers. . . so guess if you do not know an answer. • It is your responsibility to look at the overhead or blackboard about every 15 minutes and to incorporate any relevant information into your test. 1 Chapter 5 Consider the joint PMF of two random variables X and Y , and answer the next two questions. X 1 2 3 1 0.06 0.06 0.20 Y 2 0.06 0.06 0.18 3 0.08 0.08 0.22 1. What is P ( X ≥ 2  Y = 2)? (a) 0.24/0.30 (b) 0.06/0.32 (c) 0.20/0.30 (d) 0.06/0.20. 2. Compute P ( X ≤ 2 and Y ≤ 1) ? (a) 0.32 (b) 0.20 (c) 0.12 (d) 0.06. 3. The inside diameter of a randomly selected piston ring is a random variable with mean value 12 cm and standard deviation 0.02 cm. Sample mean diameter for a random sample of n = 16 rings follows a distribution which is centered at (a) 12/0.02 cm (b) 12 cm (c) 12/16 cm (d) 0.02/16 cm. 4. The breaking strength of a rivet has a mean value of 9000 psi and a standard deviation of 500 psi. A sample of 100 rivets is taken. What is the probability that the sample mean breaking strength exceeds 9050 psi?...
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This note was uploaded on 03/19/2012 for the course GEOG 305 taught by Professor Prout during the Spring '08 term at Texas A&M.
 Spring '08
 PROUT
 Geography

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