Chapter 2 Bad at math is a lie

Let me guess: There’s a not-insignificant part of you that’s pretty happy to be in journalism school because the math requirements are pretty minimal. Have you ever said, out loud, “I can’t do math, I’m a journalism major!” Have you ever thought “It’s okay, I’m bad at math.” Have you been bad at math your whole life?

First, you’re not alone.

Second, you’re living a lie.

That’s right. A lie. Bad at math is not a thing. And you are not bad at math. You just think you are. And it’s a destructive lie you tell yourself.

You, like me, struggled with math at some point when your friends didn’t. They kept going, you kept struggling, and suddenly they were good at math and you were not. And here you are today.

Except with journalism today, you can’t continue to live the lie. You are surrounded by data. You are surrounded by numbers. If you continue to believe you’re bad at math, you will be easy to fool by people who aren’t. You’ll be unable to see stories that are sitting there in the numbers.

In short: you won’t be a very good journalist.

The good news? This isn’t very hard. The types of math that get you in the door are really quite easy. And you can do some very powerful things.

2.1 How high school algebra won a Pulitzer Prize

If you were at all paying attention in pre-college science classes, you have probably seen this equation:

d = rt or distance = rate*time

In English, that says we can know how far something has traveled if we know how fast it’s going and for how long. If we multiply the rate by the time, we’ll get the distance.

If you remember just a bit about algebra, you know we can move these things around. If we know two of them, we can figure out the third. So, for instance, if we know the distance and we know the time, we can use algebra to divide the distance by the time to get the rate.

d/t = r or distance/time = rate

In 2012, the South Florida Sun Sentinel found a story in this formula.

People were dying on South Florida tollways in terrible car accidents. What made these different from other car fatal car accidents that happen every day in the US? Police officers driving way too fast were causing them.

But do police regularly speed on tollways or were there just a few random and fatal exceptions?

Thanks to Florida’s public records laws, the Sun Sentinel got records from the toll transponders in police cars in south Florida. The transponders recorded when a car went through a given place. And then it would do it again. And again.

Given that those places are fixed – they’re toll plazas – and they had the time it took to go from one toll plaza to another, they had the distance and the time.

It took high school algebra to find how fast police officers were driving. And the results were shocking.

Twenty percent of police officers had exceeded 90 miles per hour on toll roads. In a 13-month period, officers drove between 90 and 110 mph more than 5,000 times. And these were just instances found on toll roads. Not all roads have tolls.

The story was a stunning find, and the newspaper documented case after case of police officers violating the law and escaping punishment. And, in 2013, they won the Pulitzer Prize for Public Service.

All with simple high school algebra.

2.2 The basics of the basics

If you don’t know these, you are doomed from the start.

One of the most difficult hurdles for beginning students of mathematics to get over is notation. If you miss a day, tune out for a class, or just never get around to asking what something means, you’ll be lost. So lets just cover some bases and make sure we all understand some ultra-basic notation.

You might laugh at these, but someone reading them is looking up Gods on Wikipedia to thank. So do yourself a favor and refresh.

Symbol	Meaning	Example
+	addition	5+2
-	subtraction	6-2
*	multiplication	7*2
/	division	8/2
^	exponent	2^3
sqrt	square root	sqrt(4)

One of the most important and often overlooked concepts in basic math is the order that you do the calculations. When you have something like 5+5*5^2, which gets done first? Or, as you’ll read in the next section, what comes first when you calculate the average of a thing? The adding up of all the numbers or the division by the number of numbers?

Thankfully, math teachers have provided us an easy to remember mnemonic that you probably learned in sixth grade and forgot until now.

PEMDAS – Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction

What that means is when you look at a mathematical formula, you do the calculations in the order PEMDAS tells you. Something in parenthesis? Do that first. Is there an exponent? Do that next. Multiplication or division? It’s next and so forth. Knowing PEMDAS will save you from stupid mistakes down the road.

2.3 Spreadsheets

Spreadsheets are one of the most basic tools for data analysis. They are the Swiss Army Knife of data analysis. They’re immensely useful. But like a Swiss Army Knife, they’re useful for a lot of things, but they’re never the best tool for that thing. Statistical analysis? Spreadsheets are great for that, but there are statistics software packages that are better. Graphics and visualizations? You can do amazing work in a spreadsheet, but there are visualization packages that are better. Complex queries? It can be done with a spreadsheet, but a database is better.

But the simple truth is almost all data analysis, and data analysts, begin or end with a spreadsheet. They’re the one tool every data nerd has.

And they’re a great place to start.

But before we can get started, you have to understand some basics. If you’ve never used a spreadsheet before, you’ll learn really quickly that spreadsheets organize data into a grid. That grid is made up of Rows and Columns. Rows run left and right, Columns run up and down. The little squares in the grid? They’re called Cells. Each cell stores something. What is that something? It can be a header row, telling you what data is in each column. They can store words, numbers, dates, times, dollar figures and several other types of information.

Spreadsheets are also great calculators. But unlike your calculator you used in the past, this one harnesses your computer. To do that, you have to tell your computer that you’re computing something. That starts with an equal sign. If your spreadsheet of choice, try this.

=2+2

The formula disappeared and you got 4, right? That’s how spreadsheets work. It shows you the results of what you did. You can use any of the symbols from above and your spreadsheet will calculate them all.