Imagine Magazine - Johns Hopkins - November/December 2013 - (Page 22)

Developing Your Numbersense by Kaiser Fung Why Everyone Needs to be a Data Geek In the age of Big Data, when every day brings a flood of numbers and insights, you need to be on your toes to know if the interpretations of all this data make sense. We perceive numbers as facts, but too often they impart only incomplete knowledge. Here, I'll look at some ways numbers-and the way they're displayed- can be misleading. As a consumer of information, you need what I call "numbersense"-a critical thinking skill that will help you evaluate the statistics and charts you encounter every day. The Whole Story? Last time I went to a Starbucks café, the young woman in front of me had a tall order, five or six drinks, each delivered with a detailed recipe. The barista took copious notes on the side of the paper cups, noting, for example, that one of the lattes should be half decaf, half caffeinated. The customer continued, "For milk, I want one part whole milk, and three parts two-percent." You can do the quick math, the way your algebra teacher taught you. With four parts, each part is a quarter. One quarter of the whole is 25 percent. Three quarters of two percent is 1.5 percent. Add them up, and meet Miss 26.5 Percent! A few weeks after my Starbucks encounter, I was having dinner with a friend when low-fat milk entered our conversation. My friend, who is a 22 imagine doctor, made me realize I had become a victim of marketing by numbers. The good doctor let on that two-percent milk is only marginally less fattening than whole milk. Consumers are led (or misled) to believe that whole milk is 50 times worse when in fact, the fat content of "whole" milk is only 3.25 percent. I confirmed this discouraging news on the Starbucks website. A grande Frappuccino drink made with whole milk has 240 calories; the same drink made with two-percent milk-Starbucks's default since 2007-has only 10 fewer calories! Ten fewer calories is a trifle when the average person consumes about 2,000 a day. Instead of averaging two percent and 100 percent, I should have averaged two percent and 3.25 percent. Exit Miss 26.5 Percent, and enter Miss 2.3 Percent! Nov/Dec 2013

Table of Contents for the Digital Edition of Imagine Magazine - Johns Hopkins - November/December 2013

In My Own Words
Interested in Econ
The World in Numbers
Reckoning with Randomness
Elliptic Curves
A League of Our Own
More Than Math
Developing Your Numbersense
Where Math Meets Imagination
Selected Opportunities & Resources
Dancing in the Footsteps of My Ancestors
Off the Shelf
Word Wise
Exploring Career Options
Planning Ahead for College
Students Review
Mark Your Calendar
Knossos Game

Imagine Magazine - Johns Hopkins - November/December 2013