Tag Archives: experiment

Florence Nightingale: The passionate statistician

She brought about fundamental change in the British military medical system, preventing any such future calamities. To do it, she pioneered a brand-new method for bringing about social change: applied statistics.
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he statistics changed Nightingale’s understanding of the problems in Turkey. Lack of sanitation, she realized, had been the principal reason for most of the deaths, not inadequate food and supplies as she had previously thought.
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As impressive as her statistics were, Nightingale worried that Queen Victoria’s eyes would glaze over as she scanned the tables. So Nightingale devised clever ways of presenting the information in charts. Statistics had been presented using graphics only a few times previously, and perhaps never to persuade people of the need for social change.

Applied statistics is a tool available to all to achieve great improvement. Unfortunately it is still very underused. As George Box says: applied statistics is not about proving a theorem, it’s about being curious about things. The goal of design of experiments is to learn and refine your experiment based on the knowledge you gain and experiment again. It is a process of discovery.

Dolphin Delivers Deviously for Rewards

Deep thinkers

At the Institute for Marine Mammal Studies in Mississippi, Kelly the dolphin has built up quite a reputation. All the dolphins at the institute are trained to hold onto any litter that falls into their pools until they see a trainer, when they can trade the litter for fish. In this way, the dolphins help to keep their pools clean.

Kelly has taken this task one step further. When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on. This behaviour is interesting because it shows that Kelly has a sense of the future and delays gratification. She has realised that a big piece of paper gets the same reward as a small piece and so delivers only small pieces to keep the extra food coming. She has, in effect, trained the humans.

Her cunning has not stopped there. One day, when a gull flew into her pool, she grabbed it, waited for the trainers and then gave it to them. It was a large bird and so the trainers gave her lots of fish. This seemed to give Kelly a new idea. The next time she was fed, instead of eating the last fish, she took it to the bottom of the pool and hid it under the rock where she had been hiding the paper. When no trainers were present, she brought the fish to the surface and used it to lure the gulls, which she would catch to get even more fish. After mastering this lucrative strategy, she taught her calf, who taught other calves, and so gull-baiting has become a hot game among the dolphins…

Too bad for the poor gulls but this is pretty cool. Plus it serves gulls right, one stole my breakfast a few years ago when I was down in Florida.

Learning Design of Experiments with Paper Helicopters

Photo showing the helicopter test track by Brad

Dr. George E.P. Box wrote a great paper on Teaching Engineers Experimental Design With a Paper Helicopter that can be used to learn principles of experimental design, including – conditions for validity of experimentation, randomization, blocking, the use of factorial and fractional factorial designs and the management of experimentation.

I ran across an interesting blog post on a class learning these principles today – Brad’s Hella-Copter:

For our statistics class, we have been working hard on a Design of Experiments project that optimizes a paper helicopter with respect to hang time an accuracy of a decent down a stairwell.
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We were to design a helicopter that would drop 3 stories down within the 2ft gap between flights of stairs.
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[design of experiments is] very powerful when you have lots of variables (ie. paper type, helicopter blade length, blade width, body height, body width, paperclip weights, etc) and not a lot of time to vary each one individually. If we were to individually change each variable one at a time, we would have made over 256 different helicopters. Instead we built 16, tested them, and got a feel for which variables were most important. We then focused on these important variables for design improvement through further testing and optimization.

Test it Out, Experiment by They Might Be Giants

Put It to the Test is one of the songs on the great new Album and animated DVD from They Might Be Giants: Here Comes Science.

Are you sure that thing is true, or did someone just tell it to you.
Come up with a test. Test it out.
Find a way to show what would happen if you were incorrect. Test it out.
A fact is just a fantasy unless it can be checked.
Make a test. Test it out.

A fun song on fundamentals of experimenting to the scientific method.

Experimenting Social Network

Social media is definitely a fad filled with lots of ways to waste time. It also does have real value, ways to connect to things people care about and wish to focus on. Reddit is a good site for finding interesting resources online. Sub-reddits are topical areas within Reddit (I have set up management and investing sub-reddits). A new experiment subreddit looks very interesting:

Each experiment will go through a few threads. The first step will be a query for experimental methods. Someone will present a problem or piece of information they want to find out, and then others will suggest methods. Once this is agreed upon, it will be carried out, and a second thread will be posted detailing the method and providing a place to post results via the comments. Then, a third thread can be made to discuss the results. Having more than one thread for every experiment will make things more accessible and easier to sort.

Don’t research ways other people have experimentally determined these things. Submit original ideas to the experimental design thread. Try to come up with a novel way to discover things, but don’t be completely limited by this suggestion. This is chiefly about rediscovery, not repeating someone else’s experiment, but sometimes there’s fun and merit in that as well.

I have joined. You can go to Reddit and join this subreddit to see experiences with experimenting to learn about the world around us.

Controlled Experiments for Software Solutions

by Justin Hunter

Jeff Fry linked to a great webcast in Controlled Experiments To Test For Bugs In Our Mental Models.

I firmly believe that applied statistics-based experiments are under-appreciated by businesses (and, for that matter, business schools). Few people who understand them are as articulate and concise as Kohavi. Admittedly, I could be accused of being biased as: (a) I am the son of a prominent applied statistician and (b) I am the founder of a software testing tools company that uses applied statistics-based methods and algorithms to make our tool work.

Summary of the webcast, on Practical Guide to Controlled Experiments on the Web: Listen to Your Customers not to the HiPPO – a presentation by Ron Kohavi with Microsoft Research.

1:00 Amazon: in 2000, Greg Linden wanted to add recommendations in shopping cards during the check out process. The “HiPPO” (meaning the Highest Paid Person’s Opinion) was against it on the grounds that it would be a bad idea; recommendations would confuse and/or distract people. Amazon, a company with a good culture of experimentation, decided to run a small experiment anyway, “just to get the data” – It was wildly successful and is in widespread use today at Amazon and other firms.

3:00 Dr. Footcare example: Including a coupon code above the total price to be paid had a dramatic impact on abandonment rates.

4:00 “Was this answer useful?” Dramatic differences occur when Y/N is replaced with 5 Stars and whether an empty text box is initially shown with either (or whether it is triggered only after a user clicks to give their initial response)

6:00 Sewing machines: experimenting with a sales promotion strategy led to extremely counter-intuitive pricing choice

7:00 “We are really, really bad at understanding what is going to work with customers…”
Continue reading →

Honeybees Warn Others of Risks

Honeybees warn of risky flowers

They trained honeybees to visit two artificial flowers containing the same amount and concentration of food. They left one flower untouched, making it a “safe” food source for the bees.

On the other flower, they placed the bodies of two dead bees, so they were visible to arriving insects, but would not interfere with their foraging. They then recorded whether and how the bees performed a waggle dance on their return to other members of the hive colony.

On average, bees returning from safe flowers performed 20 to 30 times more waggle runs that bees returning from dangerous flowers.

That shows that the bees recognise that certain flowers carry a higher risk of being killed or eaten by predators, such as crab spiders or other spider species that ambush visiting bees.

Crows Can Recognize People

Crows can recognize people and remember them for years. Listen to this interesting report from NPR. Researchers alienated a crow, and then were razzed and harassed by its family and neighbors wherever they go.

Home Experiment: Tape Makes Frosted Glass Clear

Interesting result. A comment on Reddit seems plausible to me:

The surface of frosted glass is etched so that it scatters light when it hits this rough surface. The glue on the tape fills in any irregularities, letting the light pass through with much less scatterring (notice, the image is still not perfect).

Additional experimenting could include, what the view is like from the other side of the glass. What the view is like if you also put tape on the other side of the glass.

Home Engineering: Building a Hovercraft