20 March 2012

Statistical Misconception Removal

Our central city is being “deconstructed”. That’s the modern word for demolition. We live in Christchurch, New Zealand where many of our buildings were badly damaged by a string of serious earthquakes over the last 18 months, beginning on 4 September 2010. Over a thousand buildings in the central city are being demolished, because they are no longer safe. The larger ones will take up to a year to bring down, and experts have come from other parts of the world to assist in the process. It is pretty sad, really as we love our buildings. But we need to […]
15 March 2012

Seductive Causation

Causation is a seductive notion. We want to make meaning out of our world. I love playing “the beeping nose” with little children. I press their nose and it beeps. I press my nose and it whirrs. It fascinates them. They have discovered cause and effect. They can make cool sounds by pressing noses. You can keep them amused for quite some time. Cause and effect implies control. If we know what causes things we are better able to control them. Scientific endeavor is largely a search for causes. History is littered with examples of misplaced cause and effect theories. […]
23 February 2012

Drill and Rote in teaching LP and Hypothesis Testing

Drill and rote-learning are derogatory terms in many education settings. They have the musty taint of “old-fashioned” ways of teaching. They evoke images of wooden classrooms and tight-lipped spinsters dressed in grey looming over trembling pupils as they recite their times-tables. Drill and rote-learning imply mindless repetition, devoid of understanding. Much more attractive educational terms are “discovery”, “exploration”, “engagement”. Constructivism requires that learners engage with their materials and create learning by building on existing knowledge and experiences. But (and I’m sure you could see this coming) I think there is a place for something not far from drill or rote-learning […]
26 January 2012

Sampling Error Isn't

I hope you committed to a response in the box before reading this post. This is an important topic. Recently I read an amusing blog regarding poor sampling technique. The tweet that led to the link called it “a humorous look at sample error”. I’m hoping the person who tweeted meant bad sampling, because the problem is, the story was not about sampling error. And that is because sampling error isn’t. Isn’t what? It isn’t error. It doesn’t occur by mistake. It is not caused by bad procedures. There is nothing practical you can do when sampling to avoid sampling […]
3 January 2012

The meaning of the mean

Here is an exercise you might like to try on a class or individual, when introducing the mean. I have found it interesting and enlightening for all parties, especially those who think they know everything. Dr Nic: Tell me what a mean is, as if explaining it to someone who doesn’t know about statistics. Student: It’s an average. Dr Nic: Correct, however you haven’t really increased my understanding with that description. Student: It is what you get when you add all the numbers together and divide by the number of numbers. Dr Nic: That is a correct description of how to calculate a mean. Still […]
21 December 2011
Understanding
Mathematical understanding is not the only kind of understanding. Cobb and Moore (1997)
20 December 2011

Statistics for all

Let’s start with a question. Please answer it now before you read any further! Statistics, like Operations Research, is a mathematical science. However people can be intelligent consumers of statistical analysis without having to use mathematics. The statement in the box above is false. Often statistics is taught by mathematics teachers, who understand the mathematical aspects of statistics, but may never have dirtied their hands with real data. They teach the mechanics of calculating the values of standard deviations and confidence intervals, intending that this will lead to understanding. Unfortunately many of their pupils do not gain understanding from the application […]