math skills

Math Skills

And the people who know them

There is no escape. While many reporters and editors sought journalism as a refuge from math, the reality is that numbers are a fact of life in today’s newsroom.

Scott Maker

Associate Professor

School of Journalism and Mass Communications

University of Oregon

Journalists are generally aware of their math deficiencies and frequently develop elaborate ways of writing around the problem.

Kathleen Woodruff Wickham

Assistant Professor

University of Mississippi

Author of Math Tools for Journalists

• Numbers are exact. That preciseness is often what frightens reporters who are more comfortable in the verbal skills.

• In order to report accurately, start by checking the math of speakers, official reports and budgets.

• Don’t assume the person preparing the numbers has good math skills or that he/she isn’t manipulating the numbers.

• Interview the numbers with the same care that you interview people.

• For the sake of clarity, try to limit the number of numbers in each paragraph to no more than two or three.

• Try to include only one number in the lead of the story.

• Do the math for the readers.

Writing Tips

• Interpret the results in terms the reader can understand. Consider using analogies, storytelling techniques or graphics to illustrate the numbers.

• Pet Peeve: More than/over. Over is for spatial relationships. Use more than for figures and amounts.

Writing Tips

Percentages• Percentage increase• Percentage decrease• Percentage of the

whole• Percentage points

Percentage increase/decrease

Percentage inc./dec. = (new figure - old figure) ÷ old figure

Convert to a percentage by moving the Decimal two places to the right.

Example -- Percent Increase

The salary of the Oceola fire chief was raised from $46,234 to $53,679. What percentage increase was the chief’s raise?

New figure = $53,679Old figure = $46,234

Example -- Percent Increase

The salary of the Oceola fire chief was raised from $46,234 to $53,679. What percentage increase was the chief’s raise?

New figure = $53,679Old figure = $46,234

$53,679 - $46,234 = $7,445

Example -- Percent Increase

The salary of the Oceola fire chief was raised from $46,234 to $53,679. What percentage increase was the chief’s raise?

New figure = $53,679Old figure = $46,234

$53,679 - $46,234 = $7,445$7,445 ÷ $46,234 = .161 = 16.1%

Example -- Percent Decrease

Camden Community Chest decided to reduce its donation to the Funtime Preschool from $3,264 to $244. By what percentage was the donation cut?

New figure = $244Old figure = $3,264

Example -- Percent Decrease

Camden Community Chest decided to reduce its donation to the Funtime Preschool from $3,264 to $244. By what percentage was the donation cut?

New figure = $244Old figure = $3,264

$244 - $3,264 = -$3,020

Example -- Percent Decrease

Camden Community Chest decided to reduce its donation to the Funtime Preschool from $3,264 to $244. By what percentage was the donation cut?

New figure = $244Old figure = $3,264

$244 - $3,264 = -$3,020-$3,020 ÷ $3,264 = -0.925 = -92.5%

Percentage of a whole

Percentage of a whole = subgroup ÷ whole group

Move the decimal two places to the right.

Example -- Percentage of a Whole

Franklin College spends $1.2 million on its football team. The entire athletic department budget is $3.5 million. What percentage of the entire budget does the football team consume?

Example -- Percentage of a Whole

Franklin College spends $1.2 million on its football team. The entire athletic department budget is $3.5 million. What percentage of the entire budget does the football team consume?

$1.2 million ÷ $3.5 million = 0.343 = 34.3%

Percentage points

One percent is 1/100 of something. One percentage point might also be 1/100 of something if it starts with 100 %. But, one percentage point could also be something other than one percent.

Example -- Percentage points

The September unemployment rate was 5.6 percent. The October unemployment rate was 7.4 percent. By how many percentage points did the rate go up?

7.4% - 5.6% = 1.8 percentage points

Example -- Percentage points

The September unemployment rate was 5.6 percent. The October unemployment rate was 7.4 percent. By how many percentage points did the rate go up?

7.4% - 5.6% = 1.8 percentage points

If you want to calculate the percentage increase, follow the formula for percent increase.1.8 ÷ 5.6 = 0.32 = 32%

Statistics• Mean• Median• Mode

Mean

The mean is the sum of all figures in a group divided by the total number of figures. The mean is commonly called the “average.”

Example -- Mean

The following are salaries for midlevel computer technicians in the Midwest. What is the average/mean?

Corp A $45,600Corp B $54,000Corp C $47,800Corp D $62,400Corp E $50,500Corp F $48,000Corp G $64,600

Example -- Mean

The following are salaries for midlevel computer technicians in the Midwest. What is the average/mean?

Corp A $45,600Corp B $54,000Corp C $47,800Corp D $62,400Corp E $50,500Corp F $48,000Corp G $64,600

Added together the figures

= $309,200.

$309,200 ÷ 7 = $53,271.43

Example -- Median

Median is the midpoint in a grouping of numbers. To determine the median, rewrite the numbers from lowest to highest; find the figure in the middle.

$45,600$47,800$48,000$50,500$54,000$62,400$64,600

Example -- Median

Median is the midpoint in a grouping of numbers. To determine the median, rewrite the numbers from lowest to highest; find the figure in the middle.

$45,600$47,800$48,000

$50,500$54,000$62,400$64,600

Mode

The mode refers to the number appearing most frequently in a distribution of numbers. If each number appears only once, there is no mode.

Example -- Mode

The following are the number of eggs hybrid chickens laid in a given month at the Jonesboro Research Farm. What number is the mode?

12 18 24 25 24 11 28 24 25

Example -- Mode

The following are the number of eggs hybrid chickens laid in a given month at the Jonesboro Research Farm. What number is the mode?

1218 24 25 24 11 28 24 25

The most frequent number to appear, the mode is 24.

When do you use mode, median or mean?

Determine which one tells the most accurate story.

Property Taxes• Property taxes are the

largest single source of income for local government, school districts and other municipal organizations.

Calculating Tax

Tax owed = Tax rate x (assessed valued

of the property ÷ $100)

Example -- Calculating tax

Middletown is raising its local property tax from 75 cents per $100 to $1.032 per $100 assessed valuation. How much will the property owner who owns a $125,000 house pay next year if the assessed value is based on 25 percent of the appraised value.

Example -- Calculating tax

Middletown is raising its local property tax from 75 cents per $100 to $1.032 per $100 assessed valuation. How much will the property owner who owns a $100,000 house pay next year if the assessed value is based on 25 percent of the appraised value.

Old rate(100,000/100) x 0.75 = $750

Example -- Calculating tax

Middletown is raising its local property tax from 75 cents per $100 to $1.032 per $100 assessed valuation. How much will the property owner who owns a $100,000 house pay next year if the assessed value is based on 25 percent of the appraised value.

Old rate(100,000/100) x 0.75 = $750

New rate(100,000/100) x 1.032 = $1,032

Example -- Calculating tax

Old rate(100,000/100) x 0.75 = $750

New rate(100,000/100) x 1.032 = $1,032

Now subtract the new tax amount from the old tax amount:

$1,032 - $750 = $282

Business• Gross margin• Gross profit• Net profit• Assets• Current ratio• Quick ratio

Gross Margin

Gross margin = Selling price - cost of goods sold

Example -- Gross margin

Allison Bennett worked part-time for the Reynolds Review selling copies of the Sunday newspaper from a newsstand on the Circle downtown. Raines paid 90 cents for each copy and sold them for $1.25. What was his gross margin?

Example -- Gross margin

Allison Bennett worked part-time for the Reynolds Review selling copies of the Sunday newspaper from a newsstand on the Circle downtown. Raines paid 90 cents for each copy and sold them for $1.25. What was his gross margin?

1.25 - .90 = 35 cents

Gross Profit

Gross profit = Gross margin x number of items

sold

Example -- Gross profit

Allison Bennett has a margin of 35 cents per Sunday paper he sells. If she sells 50, what is her gross profit?

Example -- Gross profit

Allison Bennett has a margin of 35 cents per Sunday paper he sells. If she sells 50, what is her gross profit?

35 cents x 50 = $17.50

Net Profit

Net profit = Gross margin - overhead

Example -- Net profit

Allison Bennett pays $5 to rent a newsstand on Sunday mornings. This is her only overhead expense. What is her net profit for an average Sunday, using her gross profit figure of $17.50.

$17.50 - $5 = $12.50

Assets

Assets = Liabilities + Equity

Example -- Assets

In 2001 the Coca-Cola Company reported $11,051,000,000 in liabilities and $11,366,000,000 in equity.

Example -- Assets

In 2001 the Coca-Cola Company reported $11,051,000,000 in liabilities and $11,366,000,000 in equity.

$11,051 + $11,366 = $22,417 in assets (in millions)

Current RatioCurrent ratio is a liquidity ratio that measures the ability of a company to meet its liabilities. It is one of the ratios you will see most often.

Current ratio = current assets ÷ current liabilities

Example -- Current ratio

Pickens Media Co. has $104.8 million in current assets and $86.6 million in current liabilities.

Example -- Current ratio

Pickens Media Co. has $104.8 million in current assets and $86.6 million in current liabilities.

104,808,000 ÷ 86,600,000 = 1.21

Example -- Current ratio

Pickens Media Co. has $104.8 million in current assets and $86.6 million in current liabilities.

104,808,000 ÷ 86,600,000 = 1.21

A ratio of 1.21 means Pickens Media Co. has $1.21 in assets for each dollar in liabilities.

Quick RatioQuick ratio is a liquidity ratio that measures the ability of a company to meet its current liabilities with cash on hand.

Quick ratio = cash ÷ current liabilities

Example -- Quick ratio

Of the $104.8 million in current assets that Pickens Media holds, 424 million is cash.

Example -- Quick ratio

Of the $104.8 million in current assets that Pickens Media holds, 424 million is cash.

$424,000,000 ÷ $86,600,000 = .277

Example -- Quick ratio

Of the $104.8 million in current assets that Pickens Media holds, 424 million is cash.

$424,000,000 ÷ $86,600,000 = .277

This means that Pickens has only about 28 cents in cash for each dollar in liabilities it faces. Is that bad? Compared to the industry standard of 1.3, ($1.30 cash for each $1 of liabilities) Pickens is short on cash.

Example -- Current ratio

What does this number mean to you? Probably nothing, unless you know that the average current ratio for media companies is 1.8. By comparing, you can see that Pickens Media Co. has a current ratio that is below industry standars. That means it may not be able to pay its bills as well as another media company with a higher current ratio.

Must buy..

Math Tools for JournalistsSecond Edition

By Kathleen Woodruff Wickham

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ISBN: 0-9729937-4-6, paper, 180 pages, $16.95Student Edition: 0-9729937-5-4, 176 pages, $16.95

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Now for a really hard one…A woodcutter has chainsaw that operates at 2700 RPM. The density of the pine trees in the plot to be harvested is 470 per acre. The plot is 2.3 acres in size. The average tree diameter is 14 inches.

Now for a really hard one…

A woodcutter has a chainsaw that operates at 2700 RPM. The density of the pine trees in the plot to be harvested is 470 per acre. The plot is 2.3 acres in size. The average tree diameter is 14 inches.

How many Budweisers will the loggers drink by the time all the trees are cut?