Math Tools for Journalists: Measurements
By Kate Austin
DIRECTIONAL MEASUREMENTS
Many news stories include directional measurements that are vital to readers and should be checked by journalists by using basic math.
“The challenge here is to be able to check the work of officials, and to do it with confidence. The result is greater accuracy for the reader or viewer, which is what is important in journalism – not to be first, but to be first with what is right.” – Math Tools for Journalists, Second Edition, Kathleen Woodruff Wickham
Time, rate and distance problems:
Be sure to keep the units of measurement the same: if the rate is in miles per hour, then the time needs to be in hours and the distance in miles.
Formulas:
Distance = rate x time
Rate = distance / time
Time = distance / rate
Sample Problem:
Billy Maxwell, a reporter for the Yellow Yellowstonian, was sent to the state capital to cover a free-trade discussion. If he drove 70 mph on the interstate for 9 hours, how far did he travel?
Answer: Distance = 70mph x 9 hrs = 630 miles
Speed, velocity, acceleration, g-force and momentum:
Speed: Measures how fast something is going
Velocity: Measures how fast something is going and also indicates its direction.
Average speed: calculated by dividing the distance traveled by the time it took to get there
Formulas:
Average speed = distance / time
Acceleration = (ending velocity – starting velocity) / time
Ending velocity = (Acceleration x time) + starting velocity
G-force: an acceleration measure. One “g” represents the normal force of gravity on the Earth’s surface
To determine the speed an object was at when it hit the ground, you need the ending speed formula.
Formula: Ending speed = √ 2(acceleration x distance)
Momentum: The force necessary to stoop an object from moving.
Formula: Momentum = mass x velocity
AREA MEASUREMENTS
There are two ways to explain measurements: analogies or with numbers. Analogies, like “The casino is the size of a football field,” are great for illustrating measurements that may be otherwise meaningless. When it is easier for a person to picture a size in comparison to something they already know the size of rather than hear a specific number and try to imagine it, analogies are best. It is important that you use analogies that your readers will easily understand.
Perimeter: The outside measurement of a square or rectangle
Formula: Perimeter (of a square/rectangle) = (2 x length) + (2 x width)
*If the object has an irregular shape, add the lengths of all sides to find perimeter.
Area of squares and rectangles
Formula: area = length x width
Area of a triangle:
Formula: area = 0.5 base x height (use the two shortest sides as base and height)
Square feet, square yards: Larger areas are measured in square feet, square yards, or square rods.
Radius: the radius of a circle is the distance from any edge to the middle
Circumference: the distance around a circle
Formula: Circumference = 2∏ x radius
Formula: Area (of a circle) = ∏ x radius^2
Sample Problem:
Robin, a reporter for the Hen’s Holler, wants to know the distance around a round flower garden at Tweeter Park. The distance from the edge of the garden to the middle is 15 feet.
Answer: 2∏ x 15 = 94.2 feet
VOLUME MEASUREMENTS
Liquid Measurements apply to liquids in recipes, bodies of water and other fluids.
Rectangular solid:
Formula: Volume = length x width x height
Cord: Firewood is sold by a measurement called a cord, or 128 cubic feet when the wood is neatly stacked in a line or row. A standard cord would be a stack of wood 8 feet long, 4 feet wide and 4 feet high.
Ton: There are different types of tons:
• A short ton is equal to 2,000 pounds
• A long ton, also know as a British ton, is equal to 2,240 pounds
• A metric ton is equal to 1,000 kilograms, or 2,204.62 pounds
THE METRIC SYSTEM

The metric system is an important part of international commerce and science and as a journalist you should understand it. The international decimal-based metric system is based on multiples of 10.
Meter: the basic unit for length based on a measure that equals one 10-millionth of the distance from the North Pole to the equator along the meridian running near Dunkirk in France and Barcelona in Spain.
Mass: one gram is the mass of one cubic centimeter of water at 0 degrees Celsius.
Newton: the metric unit of force; one Newton is a force that, applied to a one-kilogram object, will give the object an acceleration of one meter per second per second.

Math Tools for Journalists
Math Tools for Journalists:
Polls and surveys, business, stocks and bonds and property taxes
POLLS AND SURVEYS
Polls: An estimate of public opinion on a single topic or question. They are most frequently used in political circles and are based on representative samples of the population.
Surveys: Usually an estimate of public opinion with multiple questions and used in a wide variety of social science settings. They are based on representative samples of the population.
What does this mean for reporting?
It is the reporter’s job to help readers understand the validity of polls and surveys.
Things to consider
Polls and surveys are most accurate when conducted by random selection so that every person in the population being studied has an equal opportunity to be selected. That eliminates surveys where subjects select themselves for participation such as web-surveys.
Ways of selecting samples
• Universe or population sampling: Involves everyone in the population. Example: The U.S. Census because every household is queried.
• Cluster sampling: Involves sampling in one area or region. For example, a sample of students enrolled in Media Writing would be a cluster sample of journalism majors.
• Multistage sampling: Involves selecting a specific geographic area, then randomly selecting sub-groups, then individual blocks and ten a smaller block. This is frequently used in national samples.
• Systematic random sampling: Involves selecting a specific number, ay 20, and using the phone book, city directory or other reference book and polling every 10th person.
• Quota sampling: Selects a sample based on known demographic characteristics. Example: in a poll on women with school-age children who work outside the home, a sample could be made of a proportionate number of women who work in offices and women who work in factories.
• Probability sampling: Involves putting all of the potential subjects in a hat and pulling out a certain percentage. This is an example of random selection.
Terms for reporting on polls
Margin of error: the degree of accuracy of the research based on standard norms. It is expressed as a percentage and is based on the size of a randomly selected sample. The more people polled, the smaller the possible error, thus the smaller the margin of error.
Confidence Level: The level, or percentage, at which researchers have confidence in the results of their research. The formal definition: The probability of obtaining a given result by chance. A confidence level of 90 percent means the research results had a 20 percent probability of occurring by chance. Researchers select the confidence level in advance based on pre-testing and previous research. **The confidence level should always be reported a part of the story because it gives readers a chance to assess the results for themselves.
Majority: More than 50 percent of votes cast
Straw poll: A nonscientific poll
Z scores and t scores: Often used in reporting the results of studies. A z score, also called a “standard score, shows how much a particular figure differs from the mean. In a z score, the standard deviation is used as the unit measure. The mean becomes zero and the first standard deviation is 1, the second is 2 and so on. Z scores can be negative or positive depending on the location relative to the mean. The t score, also called Student’s t distribution, is closely related to z scores and is used when the sample size is roughly 100 or fewer.
Formula: z score = (Raw score – mean) / standard deviation
Sample question:
If the raw score is 54, the mean is 23 and the standard deviation is .8, what is the z score?
Answer: (54 – 23) / .8 = 38.75
BUSINESS
Business news can include press releases, quarterly earning reports and annual reports.
Financial statements: Formal documents available to shareholders, regulatory agencies and other stakeholders interested in a company’s performance. These generally include some type of profit and loss report and a balance sheet.
Profit and loss: Commonly called P&L, one of the most important documents a company issues. It shows whether a company is making money or not, by subtracting expenses from income.
Gross margin: The difference between the “cost of goods sold” and the selling price. This can also, in retail settings, be called “mark up.”
EBITA: “Earnings before interest, taxes, depreciation and amortization.” This is a useful figure in comparing companies because it shows how much cash a company is earning without regard to items unrelated to current business.
Formulas:
Gross margin = Selling price – cost of goods sold
Gross profit = Gross margin x number of items sold
Net profit = gross margin – overhead
Sample Question:
Billy Joe worked part-time for Hello Magazine selling copies of the weekly magazine from a newsstand downtown. Joe paid $2.00 for each copy and sold each copy for $2.95. What was his gross margin?
Answer: $2.95 – $2.00 = $0.95
Ratios: Calculations that analysts and business owners use to evaluate a company’s cash situation, profitability, operating efficiency and market value.
Current ratio: a liquidity ratio that measures the ability of a company to meet its liabilities.
Formula: Current ratio = current assets / current liabilities
Quick ratio: a liquidity ratio that measures the ability of a company to meet its current liabilities with cash on hand.
Formula: Quick ratio = cash / current liabilities
Debt-to-asset ratio: similar to current ratio, except it includes all assets and all liabilities (the word debt is often used interchangeably with liabilities). It is a better indicator of the long-term health of a company than current ratio.
Formula: Debt-to-asset ratio = total debt / total assets
Return on assets: a profitability ratio that measures the return on the investment on all assets.
Formula: Return on assets = net income / total assets
Return on equity: a profitability ratio that measures the return on the investment made in equity.
Formula: Return on equity = net income / equity
Price-earnings ratio: a value ratio that measures the return of the investment based on stock price.
Formula: Price-earnings = market price/share / earnings/share
STOCKS AND BONDS
Investment Reports:
• Form 8-K – Companies are required to file an 8-K when a special event occurs, such as bankruptcy, major assets are bought or sold, etc.
• Form 10-K – The official audited annual report public companies are required to file. It shows assets, liabilities, revenue, etc.
• Form 10-Q – Quarterly reports of important financial information.
• Proxy Statement – A document sent to shareholders about matters on which the shareholders will vote.
Stock: When an individual buys a share of stock in a company, he or she becomes a part owner of the company; each share represents just a tiny portion of ownership.
Bond: A loan from an investor to the government or other organization selling the bond.
Formula: Current yield = (interest rate x face value) / price
Sample Question:
Randy Tripe paid $600 for a $900 bond with a 4% interest rate. What is his current yield?
Answer: Current yield = (4% x $900) / $600 = 6%
Bond Cost: The actual cost of a bond issued by a municipality; as a reporter this may be the more important calculation about bonds because readers will be interested in knowing how much those bonds will ultimately cost the park district.
Formula: Bond cost (interest) = amount x rate x years
Dow Jones industrial average: The total value of one share each of 30 select stocks divided by a figure called the divisor. The divisor takes into account stock dividends, splits, spin-offs and other applicable corporate actions (find the current divisor at www.cbot.com).
NASDAQ: National Association of Securities Dealers Automated Quotations, an automated quotation system that reports on trading of domestic stocks and bonds not listed in the regular stock markets.
PROPERTY TAXES
Property Taxes: The largest single source of income for local government, school districts and other municipal organizations; they pay for supplies, salaries, maintenance costs and just about every other day-to-day expense.
• Measured in units called mills ($0.001)
• Expressed in terms of mills levied for each dollar of assessed valuation of property
• Usually applied to assessed valuations, not to the actual price a home would sell for on the open market (the assessed value is a percentage of market value)
Relevance for Journalists:
Articles about property taxes often make the front page and understanding how property taxes are calculated is important for journalists.
Issues to be aware of when writing about property taxes
• Reappraisal – the purpose is to update real property values to reflect current market value of all taxable properties within a taxing district
• Taxation by more than one governing body – in some areas property owners pay only county taxes or only city taxes, in other areas property owners pay both
• Type of property – the percentage used to calculate the assessed value might differ based on the type of property
Formula: Mill levy = Taxes to be collected by the government body / assessed valuation of all property in the taxing district
Sample Question:
Suffolk’s municipal budget totals $458,400 for next year. What will the tax rate be if the assessed value of all the property in Suffolk is $82,255,000?
Answer: $458,400 / $82,255,000 = .00557 = 5.57 mills = $5.57 per $1000 assessed valuation
Assessed value: depends on local policies, which can mean credits and other adjustments; the mill levy is applied to assessed valuations.
Formula: Assessed value = appraisal value x rate
Calculating tax:
Formula: Tax owed = tax rate x (assessed value of the property / $100)
*Note: divide the assessed value by $1,000 rather than $100, if the rate is based on an amount per $1,000 of assessed value.
How to: get addicted to Twitter
By Kate Austin
11/21/08
How To: Get Addicted to Twitter
This fast-growing form of “micro-blogging” has users all a twitter.
With countless ways of blogging and sharing personal information on the Internet, Twitter has created an outlet to update friends, family and followers you have never met on your daily activities – in 140 characters or less.

The New York Times called Twitter “one of the fastest-growing phenomena on the Internet.” Although this form of “micro-blogging” has yet to fully catch on with the younger generation of constant communicators, which Seventeen magazine has dubbed “Generation Speed,” it is only a matter of time before they are hooked into yet another way of constantly staying in contact with their peers.
Simplicity is Key
“With its requirement for people to squeeze their thoughts into 140 characters or less, Twitter is a perfect tool for a fast-paced, mobile society,” said Janna Anderson, director of a research project called Imagining the Internet.
Becoming a Twitter addict is difficult to avoid; the simplicity of the blog hooks the everyman who is eager to connect with others. By asking one question, “What are you doing?” and allowing users to update by mobile texting, instant message, or the Web, “tweets” are easily and frequently posted.
“It’s called ‘micro-blogging’ because some people use it just to inform their friends about what they are doing minute-by-minute, for instance writing things like, ‘I just voted for Obama, and now I’m headed over to Starbucks to get my free cup of Election Day coffee,’” said Anderson.
Silencing the Constant Twitter
“Twitter is what you make of it–receive a lot of information about your friends, or just a tiny bit. It’s up to [the user],” reads the Web site. Settings can be personalized to a great extent; one can constantly be receiving their friends’ tweets on their cellular phone, or only receive certain peoples updates. There is even a setting where one can schedule Twitter to silence the updates during dinnertime.
The benefit of Twitter is the way that the question is asked. Answers to “What are you doing?” are usually rhetorical; users are not expected to reply to other people’s tweets, but have the option of doing so.
Professionals Carry a Tune
Twitter is used by large businesses to provide information regarding products and services to the public. In a way this becomes a free form of self-promotion, and a simple way to inform those who are interested. Company news from businesses such as Whole Foods Market and Jet Blue is twittered about.
Not only company news, but also public news, appears on the Twitter site. The Election 2008 page, for instance, is a continually scrolling page that is constantly updated, even now that the election is over. During the campaign period, twittered conversation consisted of live-texts from political rallies and notes from early voting stations.
Media professionals, well-known gossip news personality Perez Hilton and company officials all have a voice on Twitter; any user can follow the tweets posted by these people.
“I’m following a number of technology people and media experts; I’m getting a steady stream of data from interesting people like Tim O’Reilly, the man who coined the term Web 2.0, and Jay Rosen, a new-media columnist,” said Anderson.
Sing Your First Note
Getting started with Twitter is as easy as creating a username and password. Head to the Twitter Web site, click “Get Started Now,” and choose a name. Next, personalize your Twitter page, and start posting tweets. You’ll be a regular songbird in no time.
Editorial: Walter William’s Journalist’s Creed
By Kate Austin
11/19/08
Editorial: Walter William’s Journalist’s Creed
“I believe that a journalist should write only what he holds in his heart to be true,” this, written by the first dean of the Missouri School of Journalism Walter Williams, is one glitch in “The Journalist’s Creed.”
It is true that to write effectively, a journalist must believe in the cause; they must be devoted to the good of the public and of the world and that must resonate in the core of their being, the heart. But, a journalist’s opinions will not always be aligned with the news that they must report. To believe something in one’s heart is to hold it as the truth, but the heart is linked to emotion and therefore to personal truth over worldly and objective truth.
This line of “The Journalist’s Creed” would better read, “I believe that a journalist should write only what is true.” Passion and heart for their work should lie within the journalist and their devotion to report the truth, but the ultimate truth will not always be what they feel in their heart to be true.
The one other part of the creed that would be better off altered is in the final section. It is telling of the time in which Walter William wrote “The Journalist’s Creed,” but does not withstand the acceptance of differences that the idealistic today holds. It reads, “I believe that the journalism which succeeds best – and best deserves success – fears God and honors Man.”
In the world today where many people from differing religions practice journalism and are successful reporters, there is no need for good journalism to be God-fearing. In no way does this apply to the worth of the writing itself.
The completion of the final segment of the creed holds many important criteria for successful journalism, “independent, unmoved by pride of opinion or greed of power, constructive, tolerant but never careless” and others, therefore it would be beneficial to take out the God-fearing criteria to better encompass the differences of faith in people of the world.
Student actor Chris Wood pushes the limits
By Kate Austin
11/9/08
He wanted to be a surgeon, a surgeon and an actor. “A ‘Broadway actor’ I called it,” he said. In second grade the surgical dream faded and a decision was made: actor.
-
![but_i_do_wood2_2 Wood performs in the musical theater department's production of "Collage" in the fall of this year. "One thing I really want to focus on [for the rest of my time at Elon] is my voice," he said.](http://kataraus.files.wordpress.com/2008/11/but_i_do_wood2_2.jpg?w=233&h=300)
- Wood performs in the musical theater department‘s production of “Collage” in the fall of this year.
“One thing I really want to focus on [for the rest of my time at Elon]
is my voice,” he said.
Childhood dreams are fantastical and elaborate. Dreaming of what one wants to be when they grow up is filled with endless possibilities. For some, hard work and passion pays off. For junior musical theater major Christopher Wood, the struggle is worth the possibility of success.
Sitting comfortably as an old friend would, Wood dives back into his childhood. He tells how acting became a part of his life early on, smiling slightly at his own memories. With an older sister who participated in the local children’s theater in Dublin, Ohio, Wood was anxious to join in the fun.
“I was five years old and wanted to do [children's theater] too, but I was too young,” he said. “I think you had to be seven. So when I was seven, I did ‘Pied Piper’ with her.”
From then on, he was hooked. “I don’t think I really stopped [being in theater] after that show,” he said. Wood was lucky enough to be at a starting high school in a place that was prolific in its theater department; Dublin Coffman High performed about six shows a year, two of which each year were musicals.
It was early on in his journey that Wood got a taste of the spotlight. “My first lead role was ‘Ren’ in ‘Footloose’ [sophomore year],” he reminisced. “It wasn’t a big challenging part, but it’s one of my greatest memories because it was the first time that I was the most important part of the show; up until then I had been little characters or ensemble.”
From then on the roles kept coming. A production of “A Midsummer Night’s Dream” transformed Wood into a donkey in the role of “Bottom,” and he played bad-boy T-Bird, “Danny” in the school’s production of “Grease.”
“In high school I played all these parts that I probably shouldn’t have played for my voice type because I’m not really a tenor,” he says, letting out a deep chuckle. “They were kind of the opposite of ‘Sweeney [Todd]’ or any other part I should be playing.”
![wood2 "I made my 'Sweeney' a little younger [than other actors do]," Wood said. "I'm obviously [don't look] like I'm 40 or 50 years old."](../files/2008/11/wood2.jpg?w=300)
- “I made my ‘Sweeney’ a little younger [than other actors
do],” Wood said. “I obviously [don't look] like I’m 40 or 50 years old.”
One wouldn’t think that “Sweeney Todd” would be the ideal character for Christopher Wood to portray. With his personable nature a friendly smile, he’s the last person one would picture on a deranged killing spree. However, it is Wood’s hardworking demeanor that makes him perfect for the part.
“I know that he put months of preparation into his portrayal of Sweeney Todd,” said mentor and close friend, senior musical theater major Tal Fish. “But don’t let that dark demeanor fool you. The first time we shared the stage he was doing a spot-on Groucho Marx in “A Day in Hollywood/A Night in the Ukraine.”
Not only was Wood selected to play the lead in Elon University’s production of Sondheim’s acclaimed musical, “Sweeney Todd,” but he had been dreaming of this opportunity for a long time.
“It has been my favorite musical for so long,” he begins, his speech beginning to race in excitement. “It’s my dream role. It’s my favorite show. It’s my favorite composer. It’s great that I got the chance this early in my life [to play the part]. Most people don’t have the opportunity to play parts like this until they’re the typical age range.”
Chris Wood isn’t most people. He has worked hard to take advantage of every acting opportunity, throwing himself into parts outside of his comfort zone.
“I was in the ensemble of Chicago, so I danced, which is something you’ll never see me do – at least not well,” he said. Another role that pushed the line of normality for Wood was playing “Frank N. Furter” in the “Rocky Horror Picture Show.”
“I had to wear four and a half-inch heels and a corset,” he explained. “[The heels] hurt my feet so bad!” Laughing once again, he said, “It was a bit different than childhood dress-up.”
This summer pushed Wood in a different way. Working in Kentucky for three different shows simultaneously, his voice took “the biggest beating it ever has.”
“I only had Mondays off, and I did that for three months straight…it was hard to push through because I was busy, I was tired and I was grumpy because I didn’t have any free time,” he said, trying hard not to complain.
“I was working in this outdoor theatre in 110 degree weather with cicadas dropping like dive bombers into our heads during the shows.”
Knowing that it is his goal to continue this kind of work for his lifestyle, hopefully minus the cicada kamikazes, Wood says he realizes that he’ll still only have one day a week off, but at least he wouldn’t be in rehearsals all day long.
One tool that Elon has given Wood is the “Meisner technique.” It seems to come through in his everyday nature, as well as his acting.
“[The technique teaches] being open and ready to be done to and do anything,” he says, talking with his hands. “To listen and respond with another actor on stage, and just breathe through each moment.”
With so many successful well-known actors in the part of “Sweeney,” Wood had a lot to live up to. This concerned him a little, but with a confident smirk he knows that he doesn’t play the character the same as they do. His “Sweeney” is younger and oddly alluring.

Chris Wood and Emily Rice succeed in drawing the audience to their characters. "It's easy to get caught up on the dialect, or the fact that you know so much about the characters," he said. "You just have to know what you know, but sort of forget it so that you can just be the character."
“There are all these comparisons for the part [of ‘Sweeney’]. I mean, Johnny Depp, George Hearn and Len Cariou, the original ‘Sweeney,” he said. “There are all those from the Broadway world, where we have George Hearn. In the movie world we have Johnny Depp. Some people will like [my portrayal] better and some people may not like it, but that’s the same with every part.”
Fish swears that when he first met Wood he was “a shy, soft-spoken freshman.” He quickly became “a dominating force in the department.”
Seeing Wood sweep across the stage in “Sweeney Todd,” he is far from shy. He sends chills through the audience with resonating bass tones and a frighteningly charismatic portrayal of the crazed killer.
“He is not only a skilled, versatile actor, he is also a man of faith and integrity,” says Fish. “As his mentor, I look up to him just as much as he looks up to me.”
Wood shares the best advice he’s ever been given:
Math Tools for Journalists: tips from Wickham’s book
By Kate Austin
11/2/08
CHAPTER 1: THE LANGUAGE OF NUMBERS
Chapter one of Wickham’s book discusses the language of numbers. It is highly important to double-check the math of speakers, reports and budgets. One never knows if someone may have tweaked the numbers to sound better.
One must also know when it is appropriate to tweak the numbers in regards to rounding. Knowing when it’s appropriate to round should be straightforward. In Wickham’s example, one would never round with the number of deaths in a fire, but it is inconsequential to round the amount of salt used on town roads, increasing readability.
When beginning a sentence with a number, one must spell the number out, or better yet, alter the sentence so that it does not begin with a number.
Finally, one of the most important things a writer can do when working with numbers is to digest the numbers for the reader. Wickham suggests using analogies, storytelling tactics and graphics to explain numbers to readers.
This digestion of the numbers includes the use of appropriate language when working with numbers. For example, when speaking of figures and amounts use “more than” rather than “over” to explain a greater value.
CHAPTER 2: PERCENTAGES
There are many formulas that are useful for percentages in the news. This falls again on the digestion of numbers by the reporter for the reader. Wickham says one should never leave it to the reader to calculate percentages.
Some useful formulas include: the formula for percentage increase/decrease: (new figure – old figure) / old figure (.001) = percentage increase/decrease; for salary increase: original salary x percent increase = dollar amount of salary increase for first year; the percentage of a whole: subgroup / whole group (.001) = percentage of whole.
Another set of important formulas is used for sports statistics such as batting average, slugging percentage, and earned run average.
It is important, when working with percentages, that one realizes there is a difference between percent and percentage point. One percent is equal to one-hundredth of something, but a percentage point is based on the numbers within the equation and therefore could be anything.
Many of the numbers in a news report will be monetary amounts. Some main formulas for this topic tell how to find payments on loans (monthly payment = [original loan amount x (1 + interest rate)^total number of months x interest rate] / [(1 + interest rate) ^ total number of months -1]).
Sample problem:
Jeff Jefferson took out a loan for three semesters (15 months). How much must Jeff pay each month on a loan of 4,600 at 5.5 percent interest, compounded annually, assuming he pays back the loan in total after 15 months?
CHAPTER 3: STATISTICS
According to Wickham, statistics are important for reporting crime rates, average cost of food and student test scores. Statistics can be used to make inferences about a subject. Mean, mode and median are three ways to assess data and find an average, a middle number and a most frequent number from a set of data. It is important to know how to assess when each of these would be appropriate in most accurately representing data.
Percentiles are used to show a number in relation to the other numbers; for example, a percentile score is in relation to all the other scores. The simple formula for this according to Wickham, is: Number of people at or below an individual score / number of test takers = percentile rank.
Sample problem:
Bob Brown received the results of his state achievement tests. He received an overall score of 78. Bob found from reading the brochure that came with the results that 5,300 students took the test. Bob’s score is equal to or higher than the scores of 2,438 students. What is Bob’s percentile rank?
2,438 / 5,300 = 46th percentile
Probability can be useful to put things in perspective. Especially in regards to death numbers, or traffic accidents, where the numbers seem high but put in perspective the probability of this happening to someone is low. It is also common for health related figures to show the number of occurrences “per 100,000 people.” Wickham’s formula for this is: Deaths per 100,000 people = (total deaths / total population) x 100,000.
Sample problem:
8,045 Americans died in plane crashes over the past month. What is the probability that an American will die in a plane crash (using the “per 100,000 people” method)?
(8,045 deaths / 290 million people) x 100,000 = 2.77
CHAPTER 4: FEDERAL STATISTICS
Federal statistics such as unemployment rates and inflation rates are important to understand. The government finds the unemployment rate by the formula, (unemployed / labor force) x 100.
Another important way to understand numbers is for inflation. “Adjusted for inflation” is a common phrase meaning that the number has been changed to show what it would be equal to today. This can be found by the formula: target year value = (starting year value/ starting year Consumer Price Index) x target year CPI. The CPI values can be found on the BLS website.
Sample problem:
Jenna Jackson started as an editor in July 1990 for a salary of $7,600 a year (CPI July 1990 = 130.4). How much would this be in August 1990 dollars (CPI August =131.6)?
(7,600 / 130.4) x 131.6 = $7,670









