LSP 120 Quantitative ReasoningAbsolute vs. RelativeSlide 3Slide 4Slide 5RatesExample of a RateAnswerConfusionMore DataLSP 120QUANTITATIVE REASONINGAbsolute vs. RelativeQuantitiesABSOLUTE VS. RELATIVEAbsolute quantities are simply counts or totals of some type of dataExamples:Number of highway deaths per year per stateNumber of students in this class that earn an ANumber of adults with HIV per countryABSOLUTE VS. RELATIVEWhile absolute quantities can provide some information, it is often incomplete or simply misleadingWith relative quantities, the data is always “compared” to something.ABSOLUTE VS. RELATIVEExamples:Number of highway deaths per year per state relative to the number of drivers per stateThe percentage of students in this class that earn an AThe number of adults with HIV per country relative to the country’s populationABSOLUTE VS. RELATIVEPercentage and rate identify relative quantitiesAverage, mean, median… don’t automatically identify relative quantities unless they are averages/means/medians of relative valuesRATESWhat is a rate?When you compare some value to a fixed number of another valueFor example, highway deaths per 100 travelersInfant mortality rates – deaths per 1000 babies bornFor example0.0037 deaths per birth hard to comprehend0.037 deaths per 10 births better0.37 deaths per 100 births better still3.7 deaths per 1000 births even betterEXAMPLE OF A RATEThe average number of people killed each year in hot-air balloon accidents is 2.6The average number killed in hunting accidents is 600Which is more dangerous?ANSWERThere are two million hunters in the U.S. and just 3,000 hot-air balloonistsBalooning: 2.6/3000 = 0.000867Hunting: 600/2,000,000 = 0.0003Ballooning is approximately 3 times as more dangerous as that of hunting!CONFUSIONWhich is safer – flying or driving?Compare number of deaths killed each year in airplanes versus number killed on the highway?Or is it more accurate to compare number killed in each per mile traveled?Or is it more accurate to compare number killed in each per trip?MORE DATALet’s take a look at another example:HIV_Adults_By_Country_2001.xls(start by going to http://qrc.depaul.edu)We’ll do some sorting, change the absolute values to relative, resort, then create a map using the QRC mapping
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