24 April 2017

Graphs – beauty and truth

Graphs – beauty and truth (with apologies to Keats) A good graph is elegant I really like graphs. I like the way graphs turn numbers into pictures. A good graph is elegant. It uses a few well-placed lines to communicate what would take a paragraph of text. And like a good piece of literature or art, a good graph continues to give, beyond the first reading. I love looking at my YouTube and WordPress graphs. These graphs tell me stories. The WordPress analytics tell me that when I put up a new post, I get more hits, but that everyday […]
6 September 2016

The nature of mathematics and statistics and what it means to learn and teach them

I’ve been thinking lately…. Sometimes it pays to stop and think. I have been reading a recent textbook for mathematics teachers, Dianne Siemon et al, Teaching mathematics: foundations to middle years (2011). On page 47 the authors asked me to “Take a few minutes to write down your own views about the nature of mathematics, mathematics learning and mathematics teaching.” And bearing in mind I see statistics as related to, but not enclosed by mathematics, I decided to do the same for statistics as well. So here are my thoughts: The nature of mathematics Mathematics is a way of modelling and […]
9 November 2015

Understanding Statistical Inference

Inference is THE big idea of statistics. This is where people come unstuck. Most people can accept the use of summary descriptive statistics and graphs. They can understand why data is needed. They can see that the way a sample is taken may affect how things turn out. They often understand the need for control groups. Most statistical concepts or ideas are readily explainable. But inference is a tricky, tricky idea. Well actually – it doesn’t need to be tricky, but the way it is generally taught makes it tricky. Procedural competence with zero understanding I cast my mind back […]
5 October 2015

Summarising with Box and Whisker plots

In the Northern Hemisphere, it is the start of the school year, and thousands of eager students are beginning their study of statistics. I know this because this is the time of year when lots of people watch my video, Types of Data. On 23rd August the hits on the video bounced up out of their holiday slumber, just as they do every year. They gradually dwindle away until the end of January when they have a second jump in popularity, I suspect at the start of the second semester. One of the first topics in many statistics courses is summary […]
23 May 2014

Introducing Probability

I have a guilty secret. I really love probability problems. I am so happy to be making videos about probability just now, and conditional probability and distributions and all that fun stuff. I am a little disappointed that we won’t be doing decision trees with Bayesian review, calculating EVPI. That is such fun, but I gave up teaching that some years ago. The reason probability is fun is because it is really mathematics, and puzzles and logic. I love permutations and combinations too – there is something cool about working out how many ways something can happen. So why should I […]
9 September 2013

How to study statistics (Part 1)

To students of statistics Most of my posts are directed at teachers and how to teach statistics. The blog this week and next is devoted to students. I present principles that will help you to learn statistics. I’m turning them into a poster, which I will make available for you to printing later. I’d love to hear from other teachers as I add to my list of principles. 1. Statistics is learned by doing One of the best predictors of success in any subject is how much time you spent on it. If you want to learn statistics, you need […]
8 July 2013

Oh Ordinal data, what do we do with you?

What can you do with ordinal data? Or more to the point, what shouldn’t you do with ordinal data? First of all, let’s look at what ordinal data is. It is usual in statistics and other sciences to classify types of data in a number of ways. In 1946, Stanley Smith Stevens suggested a theory of levels of measurement, in which all measurements are classified into four categories, Nominal, Ordinal, Interval and Ratio. This categorisation is used extensively, and I have a popular video explaining them. (Though I group Interval and Ratio together as there is not much difference in […]
27 May 2013

Probability and Deity

Our perception of chance affects our worldview There are many reasons that I am glad that I majored in Operations Research rather than mathematics or statistics. My view of the world has been affected by the OR way of thinking, which combines hard and soft aspects. Hard aspects are the mathematics and the models, the stuff of the abstract world. Soft aspects relate to people and the reality of the concrete world.  It is interesting that concrete is soft! Operations Research uses a combination of approaches to aid in decision making. My mentor was Hans Daellenbach, who was born and […]
8 October 2012

Judgment Calls in Statistics and O.R.

The one-armed operations researcher My mentor, Hans Daellenbach told me a story about a client asking for a one-armed Operations Researcher. The client was sick of getting answers that went, “On the one hand, the best decision would be to proceed, but on the other hand…” People like the correct answer. They like certainty. They like to know they got it right. I tease my husband that he has to find the best picnic spot or the best parking place, which involves us driving around considerably longer than I (or the children) were happy with. To be fair, we do […]
17 September 2012

The Central Limit Theorem: To teach or not to teach

The question of whether to teach explicitly the Central Limit Theorem seems to divide instructors along philosophical lines. Let us look first at these lines. There are at least three different areas of activity within the discipline of statistics. These are Theory of statistics and research into statistics Practice of statistics Teaching statistics and related research Theory and research in statistics The theory of statistics is mathematical. It is taught and practised in Mathematics and Statistics Departments of Universities. It is possible to be an expert on the theory and mathematics of statistics while having little contact with real data. […]