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Quiz_3_fa_05_KEY

# Quiz_3_fa_05_KEY - inches Circle the correct answer but...

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ECON 2843 Name KEY Quiz 3 Fall 2005 ID # Students must show all work on problems that involve calculation. Questions 1 through 3 refer to the following. The diameter of ping-pong balls manufactured at a large factory is expected to be approximately normally distributed with a mean of 1.30 inches and a standard deviation of .04 inch. 1. What is the probability that a randomly selected ping-pong ball will have a diameter less than 1.28 inches? Circle the correct answer but also show your work. a. .3085 * b. .4801 c. .5199 d. 50% e. 69.15% f. .8632 2. What is the probability that a randomly selected ping-pong ball will have a diameter between 1.31 and 1.33 inches? Circle the correct answer but also show your work. 3. Refer to question 1. Suppose that a random sample of 16 balls is selected. What is the probability that the sample mean differs from the population mean by less than .0136

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Unformatted text preview: inches? Circle the correct answer but also show your work. a. .1331 b. .1738 c. .2662 d. .4131 e. .7338 f. .8262 * 1 4. At a street intersection in Norman, 4% of all drivers run a red light. From the very large number of drivers on a given day, 350 drivers are selected at random. What is the approximate probability that between seven and eleven of the drivers will run the red light? Circle the correct answer but also show your work. a. .0936 b. .1028 c. .1780 * d. .5874 e. .1.09 f. between .09 and .64 5. The life of computer speakers is assumed to be normally distributed with a mean of 18 years and a variance of 29.7025 years 2 . If 40 speakers are selected at random, what is the probability that the sample mean speaker lifetime will be greater than 20 years? .0102 2...
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Quiz_3_fa_05_KEY - inches Circle the correct answer but...

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