Midterm 2 (2007)

# Midterm 2 (2007) - 7[5 What is the probability that the...

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Statistics Test 2 Prof. VanderHoff Spring 2007 All work must be shown on exam to receive credit. 1. [5] A normal distribution has a mean=100. Find its standard deviation if 17% of the values exceed 144. 2. [8] What is the probability of winning 3 games in the next 5 games if the probability of winning any game is 2/3? 3. [8] Of 15 students, 5 like stat. What is the probability that 2 of 4 students randomly picked like stats? 4. [7] Calculate the probability that 3 or fewer rainy days occur during the next 15 days. The probability any day is rainy is .2. 5. [5] What size sample is required in order to have a maximum error of 5 with a 95% confidence level when the population standard deviation=12. 6 [7] What is the probability that a phone call last between 2 and 7 minutes? Time is a uniform distribution with a minimum of 0 and a maximum of 10.

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Unformatted text preview: 7 [5] What is the probability that the standard normal variable, z, is between .57 and 1.98? 8. [10] Calculate the probability that the class average test score is between 72 and 79. The number of students taking the exam is 64 and the test score mean=75 and the standard deviation=20. 9. [15] Calculate the 95% confidence interval for the population mean using the following data: x 9 6-1 2 5 7 3 9 10. [10] The mean price of purchases is \$110 and the standard deviation=\$12. What is the probability of a purchase exceeding \$90? 11. [10] Calculate the 99% confidence interval for the population proportion of liberal donors to charity. A sample of 160 liberals indicates 48 donated. 12 [10] Calculate the 95% confidence interval for the population mean. A sample of 81 had a sample mean=320 and standard deviation=25....
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Midterm 2 (2007) - 7[5 What is the probability that the...

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