SUPPLEMENTARY EXERCISESforINTRODUCTION TO THEPRACTICE OF STATISTICSFourth EditionDavid S. MooreandGeorge P. McCabeThese exercises appeared in the third edition of Introduction to the Practiceof Statistics. They were replaced in the fourth edition in the interest offreshness, but they remain high-quality exercises that supplement those inthe text.Section 1 1Chapter 1Section 1S1.1 Political party preference in the United States depends in part on the age, income, andgender of the voter. A political scientist selects a large sample of registered voters. For eachvoter, she records gender, age, household income, and whether they voted for the Democraticor for the Republican candidate in the last congressional election. Which of these variables arecategorical and which are quantitative?S1.2 Here is part of a data set that describes motor vehicles:Where City HighwayVehicle Type made MPG MPGAcura 2.5TL Compact Foreign 20 25Buick Skylark Compact Domestic 22 32Audi A8 Quattro Midsize Foreign 17 25Chrysler Concorde Large Domestic 19 27Identify the individuals. Then list the variables recorded for each individual and classify eachvariable as categorical or quantitative.S1.3 You want to compare the “size” of several statistics textbooks. Describe at least threepossible numerical variables that describe the “size” of a book. In what unit would you measureeach variable? What measuring instrument does each require? Describe a variable that isappropriate for estimating how long it would take you to read the book. Describe a variablethat helps decide whether the book will fit easily into your book bag.S1.4 You are studying the relationship between political attitudes and length of hair amongmale students. You will measure political attitudes with a standard questionnaire. How willyou measure length of hair? Give precise instructions that an assistant could follow. Include astatement of the unit and the measuring instrument that your assistant is to use.S1.5 Popular magazines often rank cities in terms of how desirable it is to live and work in eachcity. Describe five variables that you would measure for each city if you were designing such astudy. Give reasons for each of your choices.S1.6 Bicycle riding has become more popular. Is it also getting safer? During 1988, 24,800,000people rode a bicycle at least six times and 949 people were killed in bicycle accidents. In 1992,there were 54,632,000 riders and 903 bicycle fatalities.(a) Compare the death rates for the two years. What do you conclude?(b) Although the data come from the same government publication, we suspect that some changein measurement took place between 1988 and 1992 that makes the data for the two years notdirectly comparable. Why should we be suspicious?S1.7 All the members of a physical education class are asked to measure their pulse rate asthey sit in the classroom. The students use a variety of methods. Method 1: count heart beats2 Chapter 1for 6 seconds and multiply by 10 to get beats per minute. Method 2: count heart beats for 30seconds and multiply by 2 to get beats per minute.(a) Which method do you prefer? Why?(b) One student proposes a third method: starting exactly on a heart beat, measure the timeneeded for 50 beats and convert this time into beats per minute. This method is more accuratethan either method in (a). Why?S1.8 Each year Fortune magazine lists the top 500 companies in the United States, ranked ac-cording to their total annual sales in dollars. Describe three other variables that could reasonablybe used to measure the “size” of a company.S1.9 In 1993 there were 90,523 deaths from accidents in the United States. Among these were41,893 deaths from motor vehicle accidents, 13,141 from falls, 3807 from drowning, 3900 fromfires, and 7382 from poisoning. (Data from the 1996 Statistical Abstract of the United States.)(a) Find the percent of accidental deaths from each of these causes, rounded to the nearestpercent. What percent of accidental deaths were due to other causes?(b) Make a well-labeled bar graph of the distribution of causes of accidental deaths. Be sure toinclude an “other causes” bar.(c) Would it also be correct to use a pie chart to display these data? Explain your answer.S1.10 Plant scientists have developed varieties of corn that have increased amounts of theessential amino acid lysine. In a test of the protein quality of this corn, an experimental groupof 20 one-day-old male chicks was fed a ration containing the new corn. A control group ofanother 20 chicks was fed a ration that was identical except that it contained normal corn. Hereare the weight gains (in grams) after 21 days:Control Experimental380 321 366 356 361 447 401 375283 349 402 462 434 403 393 426356 410 329 399 406 318 467 407350 384 316 272 427 420 477 392345 455 360 431 430 339 410 326Make a back-to-back stemplot of these data. Report the approximate midpoints of both groups.Does it appear that the chicks fed high-lysine corn grew faster? Are there any outliers or otherproblems? (Based on G. L. Cromwell et al., “A comparison of the nutritive value of opaque-2,floury-2 and normal corn for the chick,” Poultry Science, 47 (1968), pp. 840–847.)S1.11 Table S1 contains the percent of residents 65 years of age and over in each of the 50states.(a) Make a stemplot of these data using percent as stems and tenths of a percent as leaves.Then make a second stemplot splitting each stem in two (for leaves 0 to 4 and leaves 5 to 9).Which display do you prefer?(b) Describe the shape, center, and spread of the distribution. Is it roughly symmetric ordistinctly skewed? Which states are clear outliers? Use what you know about the states toexplain these outliers.Section 1 3Table S1 Percent of residents aged 65 and over in the states (1998)State Percent State Percent State PercentAlabama 13.1 Louisiana 11.5 Ohio 13.4Alaska 5.5 Maine 14.1 Oklahoma 13.4Arizona 13.2 Maryland 11.5 Oregon 13.2Arkansas 14.3 Massachusetts 14.0 Pennsylvania 15.9California 11.1 Michigan 12.5 Rhode Island 15.6Colorado 10.1 Minnesota 12.3 South Carolina 12.2Connecticut 14.3 Mississippi 12.2 South Dakota 14.3Delaware 13.0 Missouri 13.7 Tennessee 12.5Florida 18.3 Montana 13.3 Texas 10.1Georgia 9.9 Nebraska 13.8 Utah 8.8Hawaii 13.3 Nevada 11.5 Vermont 12.3Idaho 11.3 New Hampshire 12.0 Virginia 11.3Illinois 12.4 New Jersey 13.6 Washington 11.5Indiana 12.5 New Mexico 11.4 West Virginia 15.2Iowa 15.1 New York 13.3 Wisconsin 13.2Kansas 13.5 North Carolina 12.5