SOLUTIONSMAT 167: StatisticsTest IIInstructor: Anthony TanbakuchiSpring 2009Name:Computer / Seat Number:No books, notes, or friends.Show your work.You may use the attachedequation 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 otherdocuments 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 adecimal number unless a percent is requested. Circle final answers, ambiguous ormultiple 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’sCode of Academic Ethics. You are expected to respect those guidelines.Points Earned:out of 72 total pointsExam Score:
MAT 167: Statistics, Test IISOLUTIONS p. 1 of 13Solution:Spring 2009 results.>summary( score )Min .1 stQu.MedianMean 3rd Qu.Max.17.1450.0069.2967.4482.1497.86>par (mfrow = c (1 ,2))>boxplot ( score ,main = ”Boxplotofexamscores ”)>h i s t ( score ,main = ”Histogramofexamscores ”)20406080100Boxplot of exam scoresHistogram of exam scoresscoreFrequency204060801000.01.02.03.01. The following is a partial list of statistical methods that we have discussed:1. mean2. median3. mode4. standard deviation5. z-score6. percentile7. coefficient of variation8. scatter plot9. histogram10. pareto chart11. box plot12. normal-quantile plot13. confidence interval for a mean14. confidence interval for a proportion15. one sample mean test16. one sample proportion testFor each situation below, which method is most applicable?(a) (1 point) A researcher wants to estimate the mean weight loss when on theHot BeachDiet. 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 appearsto have a normal distribution.Instructor: Anthony TanbakuchiPoints earned:/ 2 points
MAT 167: Statistics, Test IISOLUTIONS p. 2 of 13Solution: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 anormal quantile plot. The data should fall close to a line on the Q-Q norm plot if ithas 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.