STAT3502ExamReview - STAT 3502 EXAM REVIEW QUESTIONS 1 When...

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Understandable Statistics: Concepts and Methods
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Chapter 5 / Exercise 24
Understandable Statistics: Concepts and Methods
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STAT 3502 EXAM REVIEW QUESTIONS1. When human beings assemble widgets, the proportion of defective widgets is known to be 0.04. A robot assembled 500 widgets and 12 of them were defective. Is there evidence to support the hypothesis that robots are better at assembling widgets? If so, at which significance levels is the evidence statistically significant? 2. Adam takes a random sample of 8 oranges and Eve takes a random sample of 12 apples. Adam's sample of oranges yields an average weight of 15 ounces with a standard deviation of 4 ounces. Eve's sample of apples yields an average weight of 12 ounces with a standard deviation of 2 ounces. Conduct a hypothesis test at the 5% level of significance to determine if there is a difference in the average weight of apples and oranges using (i) the p-value method, (ii) the rejection point method, and (iii) the confidence interval method. You may assume the weights of apples and oranges both follow approximately normal distributions. 3.The time until failure of iPod Nanos follows an exponential distribution with a mean of 20,000 hours. (A) What is the probability that a randomly selected iPod Nano would fail within 10,000 hours of use? (B) Consider a random sample of 12 iPod Nanos. What is the probability that at least 4 of them fail within 10,000 hours of use? (C) Consider a random sample of 120 iPod Nanos. Approximate the probability that at least 40 of them fail within 10,000 hours of use? 4. The probability of a student passing STAT 2606 is 0.80. The probability of a student passing the course if they study for at least 10 hours is 0.90. The probability they study for at least 10 hours is 0.60. What is the probability that a randomly select student... (A) ...studies for at least 10 hours and passes the course? (B) ... studies for less than 10 hours and passes the course? (C) ... studies for at least 10 hours but fails the course? (D) ... studies for at least 10 hours or passes the exam, or both? (E) ... fails the course given they studied for at least 10 hours? (F) ...they studied for at least 10 hours given that they passed the course? Also, are the events of a student “passing the course” and “studying for at least 10 hours” independent? Are they mutually exclusive events?
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The document you are viewing contains questions related to this textbook.
Understandable Statistics: Concepts and Methods
The document you are viewing contains questions related to this textbook.
Chapter 5 / Exercise 24
Understandable Statistics: Concepts and Methods
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Expert Verified
5. Let Xrepresent the number of coffees your statistics professor drinks on a randomly chosen day. probability distribution of Xis described by the following probability table (A) What is the approximate sampling distribution of the sample mean and why? (B) Approximate the probability that the average number of coffees your professor drinks in those 40 days is more than 1.80. 6.A quality control technician at Moo Moo Milk Inc. took a random sample of 19 “2 litre” milk containers from a one hour production run. The weights (in litres) of the 19 containers are given in the following (split) stem-and-leaf plot. LEAF UNIT = 0.01 19 | 123 19 | 55689 20 | 111244 20 | 5778 21 | 21 | 6 (A) What are the values of the median, lower quartile (Q1), and upper quartile (Q3) for this data set? (B) Construct a box plot for this data set. 7. Lightning strikes are the leading cause of forest fires during forest fire season. Therefore, in models The

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