By Matt Holzapfel
This part of the Abridged Math Tools for Journalists Series will be focused on Chapters 1-4 of the book “Math Tools for Journalists” by Kathleen Woodruff Wickham.
Chapter 1: The Language of Numbers
“Numbers are precise” the book starts. While many journalists may think that entering the professional world of communications means they will never have to pick up a calculator or protractor again, they’re not wrong. They will, however, need to be able to understand and accurately include numbers in their reporting. These numbers can and will vary from dollar values to test scores, from pollution statistics to standard deviation statistics, and so much more.
The first subsection of this chapter details some style tips to get your number-incorporated writing into gear. It also lays out some tips for writing numbers and language with numbers and statistics. For example, you should always do the math for your readers. If they have to do it themselves, they may lose interest and not see the math as worth their time. For slang expressions such as “thanks a million” or “I owe you one”, always write out the numbers in those expressions. If there are results to display, interpret those results in terms that the reader can understand, try using analogies, storytelling techniques or graphics to “illustrate the numbers.” The chapter also provides some writing and language tips, such as when to use among vs when to use between, compared to vs compared with and different from vs different then. What an interesting way to combine math and grammar to make journalism. Some final tips from the chapter, avoid the word “fold” in terms “five-fold increase” as it could be confusing for readers. Use higher and lower when describing temperatures as opposed to warmer and colder.
Practice Problems: Pick the correct term to use in each sentence
- Dave’s car is (farther/further) away than my car
- The temperature was much (warmer/higher) yesterday
- This car’s gas tank is only (one-quarter/ 1/4) as big as the other car.
Chapter 2: Percentages
Often times, journalists are faced with numbers that could be more clearly explained if they were converted to percentages. Because of this, it is important for reporters to know how to turn numbers and ratios into percentages. There are three most common uses of percentages in journalism: percentage increase/decrease, percentage of the whole, and percentage points. The first one, increases and decreases in percentage is fairly simple, to find it we take the old number and subtract it from the new number, then take that difference and divide by the old number. Next, there are percentages of a whole. To find that we take the subgroup number and divide it by the whole group number. Examples of this statistic are: finding out what percentage of a budget was used for a certain event/item, finding the percentage of students at a school who fit certain criteria or figuring out the percentage of baseball games on a certain day that were televised. These are only a few examples out of millions that percentages can be used for. The third and final use of percentages in journalism is percentage points. It is important to distinguish between percent and percentage point. One percent is one one-hundredth of something, while one percentage point is seen, for example, if a company holds 5 percent of the market for a product, but then loses one percentage point and its new market share is 4 percent.
- The average salary for local law enforcement officers was raised from $45,000 to $52,500. What is the percentage increase of the average salary?
- I had $250 dollars to spend, I spent $70 on a textbook for my journalism class, what percentage of my money did I spend?
- The unemployment rate fell from 8% to 4.7% over the last 3 years. By how many percentage points did the unemployment rate decrease?
Chapter 3: Statistics
Behind percentages, statistics are reporters most common interaction with numbers. Common statistics found in reports are crime rates, the average cost of food at the grocery store, school student test scores and much more. Statistics are often used in research to make accurate inferences about a certain topic. It is important that journalists have a basic understanding of statistics and the role played by the manipulation of numbers. Journalists are often asked to evaluate surveys and studies, and unless they know how the numbers were used they cannot report accurately on the results. The first statistic is Mean, which is the average of a set of numbers. Next, there is Median, the midpoint in the group of numbers. Lastly, there is the Mode. The mode is simply the number that occurs most often in a number set. Another statistic that doesn’t usually go along with mean, median and mode is percentile. A percentile is a number that represents the percentage of scores that fall at or below the designated score. For example, a test-taker with a score in the 75th percentile knows that 75 percent of those who took the test scored lower than he did. To find percentile rank for test scores, take the number of people below an individual score and divide it by the total number of test takers. Lastly, there is standard deviation. Standard deviation simply tells us how much a group of figures varies from the norm. A high standard deviation means there are inconsistent results, and a low standard deviation means that the figures are consistently grouped around the mean.
- Find the mean, median, and mode for the following number set:
- 15, 30, 7, 28, 74, 16, 50, 30
Chapter 4: Federal Statistics
The federal government provides a constant stream of information of interest to the public, from inflation figures to unemployment numbers. Reporters should understand where these numbers come from and how they can be used. Unemployment is reported by the U.S. Department of Labor, Bureau of Labor Statistics. The unemployment rate is defined as the percentage of the labor force that is unemployed and actively seeking work. Next, there are inflation and Consumer Price Index numbers. Inflation is an issue that journalists frequently face, and it is measured by the Consumer Price Index. Inflation is a general increase in prices and fall in the purchasing value of money.
- What was the GDP for the United States for 2005? For 2008?
Answers to Practice Problems:
Chapter 1: 1. Farther 2. Higher 3. One-quarter
Chapter 2: 1. 16.67% 2. 28% 3. 3.3 percentage points
Chapter 3: 1. Mean = 31.25 Median = 29 Mode = 30
Chapter 4: 2005 = $13.09 trillion 2008 = $14.72 trilion