Sherman E. DeForest

As this year draws to a close, I need to rethink my priorities in life. This series was started as my own attempt to coax at least a few people into using the tools of rational thought and the scientific method in their daily lives without forcing them to become professional scientists.
My tools have been […]

Last week I presented a magic trick in which a magician leaves the room while five cards are chosen from a pack by a volunteer. The assistant selects one of the five and gives it to the volunteer. The remaining four cards are placed on a table next to the deck. The magician re-enters, picks […]

After several columns looking at problems with real life situations such as political hit pieces, it is past time for a magic trick. This one, like all good tricks, appears in many variations, and I do not know where it originated. If anyone knows its history, tell me, and I will give it credit. Several […]

Last week I wrote about receiving a political quiz that used quotes from Hillary. Several people commented unfavorably on it because of the subject matter. That is, this column is advertised as being about decision theory, statistics, and probability. What am I doing writing about a political hit piece (without regard to which side is […]

Just when I was despairing of finding an appropriate topic for this week, I received an email that hit the spot. Of course it is a political statement.
To keep the record clear about what follows, I am not an active Hillary supporter, and I certainly do not support the Bush policies. Other than that, I […]

Bern Muller’s comments about the proper use of stereotyping are insightful, but need some further discussion to be totally correct. He distinguishes between well-defined group attributes and unknown individual attributes. Statistically men are significantly taller than women, but many women are taller than me. Similarly men on the average have larger lung capacities than women. […]

In response to my comment last week about the potential usefulness of stereotyping, David posted an insightful observation. He says that not only are stereotypes useful, but that they are necessary. His comment goes to the heart of some very serious issues that are the reason I write these columns.
The success of human beings in […]

While I try to intermix artificial puzzles with real-life uses of rational thinking, sometimes the incorrect use of words to win arguments in real life overwhelms me in waves. Of course this most often happens during the electioneering season, but since we have evolved from having periodic elections to a continuous campaign, political malpractice of […]

About the only time I deviate from fun puzzles and logical discussions is when something so egregious happens that the urge to rant overcomes my thin layer of civilization. Today’s rant can be partially forgiven because at the heart of it is a concern about logical thinking and actions.
The culprit is Time Warner again. […]

The fallacies I posted last week have led me into some other difficulties. This time the problems are irrational, but real nonetheless. Consider the case of the writer who was trying to help combat child abuse by quoting the statistic that in interviews with pedophiles, 86% of them said they were homosexual and therefore homosexuals […]

We discussed the Prosecutor’s Fallacy in the past, but I recently found an excellent example of it in our local paper. To recap, the classic example of the fallacy goes something like this:
In the maneuvering for what data was to be allowed in OJ’s murder trial, the prosecutor wanted to introduce the fact that OJ […]

In the last few columns, we have explored some unexpected properties of noise, and we could easily continue that line of thought for a whole book. There is much more to noise than meets the ear. However, I recently discovered a new book that is peripherally related to the main subject of this series. The […]

Last week I featured some of the strange properties of noise and how they affect probabilities of events. Probabilities are what we use to make decisions. Therefore an understanding of the nature of noise in the data that comes to us is important. Contrary to common belief, not all noise follows a gaussian distribution with […]

This week I have been brushing up on noise. Why noise? This series deals with probability and statistics. Noise is related to probability. Random fluctuations are usually dismissed as noise. Many engineers devote their whole careers to fighting noise, knowing that in the end, noise will win. The struggle reminds me of Odin trying to […]

Based on some questions I received this week, the distinction I recently made between statistics and probability was not clear. Statistics are the record of past events. Probability deals with future events. The statistics are what they are. That is not controversial. However, the way statistics get interpreted to derive a probability to some accuracy […]

A friend pointed out to me that the dice puzzle of last week is very similar to one posted here. However, the variation posted there (#50) is more complex. Still, it is easily solved with the simple tools of probability.
Again we throw a handful of dice, but instead of asking how many dice we would […]

The puzzle last week attracted enough interest that I thought you might like another puzzle based on probability. This one involves throwing dice. Assume you have a bucket of normal dice. You pick up a handful and throw them. How many dice should you throw to have an even chance of having each face (1-6) […]

After several weeks of heavier items, here is a puzzle just for the fun of it. I was challenged by it, but instead of deriving the answer from scratch, I recognized it as being related to a probability puzzle we have featured before in several modes. Here is the puzzle, followed by the related one […]

This week I was taken to task a bit by a friend who claimed that decision theory was ultimately atheistic and opposed to higher values. Lest anyone else think such a thing, I need to respond. That simply is not true. The charge of atheism implies an active opposition to theism (the belief in an […]

The definition of “useful puzzle” is loose. This week I encountered some puzzles that I think are useful, but they are not the usual things I present here. My wife and I stopped at a little thrift store where she likes to hunt for bargains. As a matter of policy, they do not carry electronic […]