EXS_EX.2.2009.Spring - SOLUTIONS MAT 167 Statistics Test II Instructor Anthony Tanbakuchi Spring 2009 Name Computer Seat Number No books notes or

# EXS_EX.2.2009.Spring - SOLUTIONS MAT 167 Statistics Test II...

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SOLUTIONS MAT 167: Statistics Test II Instructor: Anthony Tanbakuchi Spring 2009 Name: Computer / Seat Number: No books, notes, or friends. Show your work. You may use the attached equation sheet, R, and a calculator. No other materials. If you choose to use R, write what you typed on the test. Using any other program or having any other documents open on the computer will constitute cheating. You have until the end of class to finish the exam, manage your time wisely. If something is unclear quietly come up and ask me. If the question is legitimate I will inform the whole class. Express all final answers to 3 significant digits. Probabilities should be given as a decimal number unless a percent is requested. Circle final answers, ambiguous or multiple answers will not be accepted. Show steps where appropriate. The exam consists of 19 questions for a total of 72 points on 13 pages. This Exam is being given under the guidelines of our institution’s Code of Academic Ethics . You are expected to respect those guidelines. Points Earned: out of 72 total points Exam Score:
MAT 167: Statistics, Test II SOLUTIONS p. 1 of 13 Solution: Spring 2009 results. > summary( score ) Min . 1 st Qu. Median Mean 3rd Qu. Max. 17.14 50.00 69.29 67.44 82.14 97.86 > par (mfrow = c (1 , 2)) > boxplot ( score , main = ”Boxplot of exam scores ”) > h i s t ( score , main = ”Histogram of exam scores ”) 20 40 60 80 100 Boxplot of exam scores Histogram of exam scores score Frequency 20 40 60 80 100 0.0 1.0 2.0 3.0 1. The following is a partial list of statistical methods that we have discussed: 1. mean 2. median 3. mode 4. standard deviation 5. z-score 6. percentile 7. coefficient of variation 8. scatter plot 9. histogram 10. pareto chart 11. box plot 12. normal-quantile plot 13. confidence interval for a mean 14. confidence interval for a proportion 15. one sample mean test 16. one sample proportion test For each situation below, which method is most applicable? (a) (1 point) A researcher wants to estimate the mean weight loss when on the Hot Beach Diet . The researcher takes a random sample of 100 people’s weight loss who used the diet. Solution: Construct a confidence interval for a mean. (b) (1 point) A student needs to conduct a one-sample mean test on a sample of 25 measure- ments. Before conducting the test, the student needs determine if the sample data appears to have a normal distribution. Instructor: Anthony Tanbakuchi Points earned: / 2 points
MAT 167: Statistics, Test II SOLUTIONS p. 2 of 13 Solution: Plot the data with a histogram and see if it looks like a normal distribution. If there are no outliers and it does not appear skewed, then closely analyze it with a normal quantile plot. The data should fall close to a line on the Q-Q norm plot if it has a normal distribution. (c) (1 point) The US Bureau of Labor Statistics wants to test the claim that the unemploy- ment rate is above 9 percent using a random sample of 500 people.
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