Statistics Professor Hides Pictures, Messages in Problem Solutions

Apr 11, 2007
Statistics Professor Hides Pictures, Messages in Problem Solutions
Students who solve a statistics problem correctly see images like this one appear on their computer screens. Credit: NC State University

Say you’re an aspiring statistician who has just spent hours trying to figure out the answer to a particularly thorny problem. As you plug the final numbers into the computer program you’re running in order to confirm your analysis, an image takes shape on the screen: Homer Simpson, working a problem on a blackboard. What would your reaction be?

For students of Dr. Len Stefanski, professor of statistics at North Carolina State University, it’s usually more “Whoa!” than “D’oh!”

Stefanski has developed a method for hiding messages and pictures in data sets that only appear when a student or statistician has correctly analyzed the data via regression analysis, a statistical process for studying how one variable depends on others.

His innovative approach to making statistical analysis fun is featured in the May edition of The American Statistician.

“Regression analysis is used in every scientific field,” Stefanski says. “It’s a way to describe how one variable depends upon other variables – for example, you can use regression analysis to discover how blood pressure is affected by cholesterol, weight, diet and other risk factors. Or how temperatures in different parts of the ocean might affect the number of hurricanes that occur in a given season.”

When statisticians do regression analysis, they use computer programs to help them discover trends and variability within a given set of data. The programs plot the data as dots in an onscreen graph. A statistician looking at the relationship between height and weight, for example, would expect the general trend in the graph to be that weight increases with height – and that the majority of the dots in the graph would fall along that trend. However, there are always exceptions – people who don’t fit the pattern or trend. These exceptions would show up as “scatter” in the computer model, or random dots on the screen.

“The challenge for the statistician is to find the correct trend in a data set,” Stefanski says. “If you’ve done the analysis correctly and extracted the trend from the data, then all you should be left with onscreen when you’re finished is the random scatter, and I wanted to find a way to make the payoff for getting the right answer a bit more interesting for students.”

Stefanski created a simple computer program that allowed him to “hide” images or messages in data sets. When a student successfully identifies and removes the trend data from the set, the message or picture is revealed in what is known as a residual plot. He has made the data sets available to colleagues and the public on his Web site, and will make the computer program he created available soon as well.

“It’s not a terribly efficient means of encryption,” Stefanski says, “but it certainly makes statistical analysis more visually interesting.”

Source: NC State University

Explore further: New study utilizes Kinect for Windows technology to teach elementary school students geometry

add to favorites email to friend print save as pdf

Related Stories

Davos elites warned about catastrophic cyberattacks

1 hour ago

Attacks on power plants, telecommunications and financial systems, even turning all of Los Angeles' traffic lights green: Davos elites were warned Saturday of the terrifying possibilities of modern cyber terrorism.

Recommended for you

New tattoos discovered on Oetzi mummy

3 hours ago

With the aid of a non-invasive photographic technique, researchers at the EURAC-Institute for Mummies and the Iceman have been able to show up all the tattoos on the man who was found preserved in a glacier, ...

Study identifies common elements of STEM schools

3 hours ago

Science, technology, engineering and mathematics schools vary in many ways, but they share eight major common elements. So finds a nationwide study of 23 STEM schools conducted by the University of Chicago's Outlier Research ...

Long dry spell doomed Mexican city 1,000 years ago

5 hours ago

Archaeologists continue to debate the reasons for the collapse of many Central American cities and states, from Teotihuacan in Mexico to the Yucatan Maya, and climate change is considered one of the major ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.