## Ch. 1-4 Math Tools

Journalists generally don’t like numbers, but numbers and math are a necessity in reporting. It adds necessary details that if can either make the story more informative or completely destroy the credibility of an article or writer if wrong.

**Language**

When writing numbers in an article, the reporter has the the responsibility to work out the math for readers – readers should never have to figure it out themselves. The best way to keep it simple and easy for readers to understand is to follow basic style rules regarding when to spell out numbers and how to make them most manageable.

The following numbers should be spelled out: single digit numbers (1-9), fractions less than one, a position or order in ranking for first through ninth, the start of a sentence (unless it is a date) or if an organization spells a number out in its name.

The following numbers should be written in numerals: multiple digit numbers, position or order in ranking higher than tenth (numeral and superscript), if an organization leaves it as a numeral in its name, addresses, dates, highway destinations, percentages, speeds, temperatures, times, weights, with money, ages or slang. The word minus should also be spelled out rather than using a dash or hyphen.

A combination of numerals and words can be used for numbers larger than 1 million. A mixture of numerals and words is also appropriate in a serious of numbers.

It is good to round large numbers in writing if the specific number is unnecessary and it will make it easier for the reader. Some cases, such as deaths, require specific numbers. If a number is rounded, it should be rounded to one decimal point if possible.

Even though numbers add important information to an article, it is important to try to limit how many numbers are in each paragraph. Two or three is about the limit in body paragraphs, and one in the lede.

**Percentages **

Percentages are a common in journalism and can help readers have a better sense of the numbers a writer is presenting.

To determine a percentage increase or decrease, the formula is simple: Percentage increase or decrease = (new figure minus old figure) divided by old figure. Then, move the decimal to places to the right. For percent decreases, the number should be negative.

Finding the percentage of a whole can help give readers perspective of how much of an impact something has. In this case, the percentage of a whole= the subgroup divided by the whole group. Again, the decimal point should be moved two places to the right.

A percentage point is complete different from a percent. A change in percentage points would be changing from 8 percent to 9 percent, as opposed to determining that 2 is 25 percent of 8. To determine percentage points, subtraction is all that is needed.

To convert a fraction to a percentage, divide the numerator by the denominator, then move the decimal point two places to the right.

For interest, proper vocabulary is necessary. The principal is the amount of money borrowed, and the money paid in addition to this is the interest. The rate is the percent charged for interest.

To determine simple interest, the interest = the principal times the rate (as a decimal) times the number of years.

Compounding interest, another type of interest occurs when the interest is added to the original principal, and then the interest is re-calculated the next time from the result of that.

While interest is usually annual, payments on loans are usually monthly. These are compounded, and the formula is more complex, and an advanced or online calculator makes it much easier.

**Statistics**

Statistics can be helpful, but must always be used with the understanding that they can be easily manipulated to support what someone wants to present.

There are different types of averages, and the most common is the mean. To find the mean, simply add all of the numbers together, then divide by the number of numbers. To find the median, arrange all of the numbers in ascending or descending order, then find the middle point. If there is an even number of number, find the mean of the two middle numbers. The mode is the number that appears most often in a group of numbers. Which should be used for what articles should be determined on a case-to-case basis so as to present the story most accurately.

Percentiles can also help readers determine where something ranks on a scale. To determine a percentile rank, divide the number of people at or below an individual score by the number of test takers. To determine how many people scored below that level, multiply instead of divide.

To determine how similar a number or group of numbers is to the rest of the numbers, standard deviation can be used.

Probability shows how likely something is to occur. To determine the probability, divide the number of people or things affected by the total number of people or things. To make this a “one out of ##” statement, divide one by the probability.

**Federal Statistics**

Even with an abundance of information available for reporters, it is impossible to present the figures associated with the federal government if the reporter does not know how to use the information.

Unemployment is a common concern in journalism, but to use the figures associated with it, it is important to know how and why the numbers are calculated. To determine the unemployment rate, divide the number of unemployed people by the labor force (anyone older than 16 who has a job or has looked for one in the past four weeks) then multiply by 100. When using these numbers though, it is important to keep in mind that the Department of Labor is in charge of calculating these numbers from a small sample.

Inflation, a common trend, also appears in reporting often. The Consumer Price Index can be used to present this. To adjust for this trend when comparing current prices to older ones, there is a calculator available on the Bureau of Labor Statistics Web site.

The Gross Domestic Product helps readers determine the value of a nation’s economy’s production.This can be used to determine whether the economy of a country is in good or bad health. This information is collected and computed by the U.S. Bureau of Economic Analysis.

Trade balance compares the number of imports to the number of exports. With a compilation of information from a variety of sources, the trade balance = the number of exports minus the number of imports. If it is negative, it is considered a trade deficit.

**Practice**

If the University of Tennessee football team has played 11 games this fall, but only won 4, what percentage of games has the team won?

In September 52.2 percent of Elon students looked at JuicyCampus.com weekly. In October, 21.2 percent of students still looked at Juicy Campus.com weekly. How many percentage points has this changed?

If three copy editors get paid $20 per issue, five designers get paid $25 per issue, and six section editors get paid $30 per issue, what is the average salary for The Pendulum executive staff? Which average should be used?

For the medical school she is applying to, Sarah should be in the in the 94th percentile of test takers to have a chance. If 1,736 students took the test, how many people have to score the same or below her?

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**Tags:** federal statistics, math language, percentages, statistics

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