By Christina Elias

Chapter 1: The Language of Numbers

Journalists don’t typically consider math a part of their job description, but numbers play an important role in storytelling. Numbers can show problems or progress in ways that words can fail. Because of their importance, all journalists should have a basic understanding of how to use numbers as reporting tools.

Because numbers are so important, writers should fact-check before including figures in an article. Numbers themselves may not lie, but the humans who do the calculations may make mistakes or try to manipulate them – “interview the numbers with the same care that you interview people.” Once you know the numbers are right, break them down and give readers a digestible version.

Chapter 2: Percentages

Many times, percentages offer a clearer picture to readers than raw numbers would. In those cases, it’s the duty of the reporter to accurately convert the numbers so they’re more applicable to readers’ lives. For almost any calculation, there is a formula any journalist can plug the data into.

Formulas to know:
  • percentage increase/decrease = (new figure – old figure) ÷ old figure, then move decimal two places to the right for the percentage
  • percentage of a whole = subgroup ÷ whole group
  • fraction to percent = complete the division and divide the numerator by the denominator
  • interest = principal x rate (as a decimal) x time (in years)
  • payments on loans
    • A = [P x (1 + R)^N x R] ÷ [(1 + R)^N – 1]
      • A = monthly payment
      • P = original loan amount
      • R = interest rate expressed as a decimal and divided by 12
      • N = total number of months
  • interest on savings
    • B = P(1+[R ÷ T])^T
      • B = balance after 1 year
      • P = principal
      • R = interest rate
      • T = number of times per year the interest is compounded

Chapter 3: Statistics

Statistics are vital information reporters can use to show the breadth of a topic. Journalists also often have the duty to break down the results of different surveys or studies, which is dependent on the reporter’s grasp of numbers, how they were used and what they can tell us.

Basic formulas/techniques to know:
  • mean: the sum of all figures, divided by the total number of figures
  • median: write the figures in ascending order and then find the number in the middle
  • mode: find which number appears throughout the list most frequently
  • percentile: a number that indicates what percent of scores fall above or below a certain benchmark
    • percentile rank = (number of people at/below an individual score) ÷ (number of test takers)
    • OR the number of people scored at or below that level = (percentile) x (number of test takers)
  • probabilities: the likelihood of something occurring, most often expressed in a ratio

Chapter 4: Federal Statistics

Much of the information the government provides is in the form of numbers, which falls under the jurisdiction of journalists to decipher and break down for readers. This includes things like inflation figures, unemployment rates, trade balance, the country’s gross domestic product (GDP) and annual budget.

Formulas to know:
  • unemployment rate = (unemployed ÷ labor force) x 100
  • monthly inflation rate = (current Consumer Price Index – prior month CPI) ÷ prior month CPI x 100
  • trade balance = exports – imports

Give it a go with practice problems

  1. Of Elon University’s 5,903 undergraduate students, 170 are journalism majors. What percentage of the student body are journalism majors?
  2. There were 180 journalism majors at Elon during the 2015-2016 academic year. During the 2016-2017 year, that number dropped to 170. What percentage did that number decrease between the two years?
  3. Find the mean of the following data set: 42, 54, 65, 47, 59, 40, 53
  4. Figure out the current unemployment rate if
  5. If the U.S. exported $167.1 billion worth of energy sources in 2014, but imported $355 billion, what was the trade balance for that year?

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