People, with good reason, hate stereotypes about their professions.

A

recent post on

*PR Daily* described some of the most annoying generalizations about PR professionals. One that was left off the list:

*PR pros (and writers and editors) bad at math*.

I wouldn’t say we’re bad at math; maybe it’s that we don’t like math. After all, we went to school to learn how to write and edit, not solve differential equations. The one math course I took for my undergraduate degree in journalism was called “Math: Its Spirit and Use.” So I get it: Math is not for everyone.

It is important to be math literate, to do more than just nod and smile politely when someone starts talking about compound interest or exponential growth. So here is a primer on math terms for writers.

(Definitions from

math.com and

about.com.)

**Accuracy—**how close a measured value is to the actual value.

**Precision—**how close measured values are to each other.

**Area—**the amount of space inside a two-dimensional object such as a triangle or circle.

**Circumference—**the distance around a circle.

**Diameter—**a line passing through the center of a circle that connects two points on the circumference.

**Perimeter—**the distance around a two-dimensional shape.

Radius—the distance from the center to the edge of a circle.

**Cardinal number—**numbers that indicate quantity, such as one, two, three.

**Ordinal number—**words that indicate order, such as first, second, third.

**Simple interest—**interest that is computed from only the original balance no matter how much money has accrued so far.

**Compound interest—**interest that is earned on the original balance and the interest already accrued.

**Average—**a central value of a set of numbers, calculated by adding up all the numbers and dividing by how many numbers there are.

**Mode—**a number that occurs most often in a list. 5 is the mode of 1,2,3,5,4,3,5,5

**Median—**the middle number in a series of numbers arranged in order of size; 88 is the median of 72, 75, 88, 90, 97.

**Range (statistics)—**in a series of numbers, the difference between the lowest and highest values.

**Normal distribution—**when data is distributed in a “

bell curve.”

**Standard deviation—**the measure of how far data is from the mean. The more spread apart the data, the higher the deviation.

[**RELATED:** Get advanced writing and editing tips from Mark Ragan and Jim Ylisela—choose from multiple cities!]

**Exponential growth**—a model of growth in which the rate of growth is proportionate to the amount present. This model is used for inflation and population growth.

**Logistic growth**—a model for a quantity that increases quickly at first and then slows as it approaches an upper limit. This model is used to describe increasing use of a new technology, spread of a disease, or saturation of a market.

*PR Daily *readers, have any other math terms to add?

*Laura Hale Brockway is an Austin-based writer and editor and a regular contributor to PR Daily. Read more of her work at impertinentremarks.com.*

(Image

via)