Dr Nic’s blog

28 December 2011

Re Solutions

In this time of New Year resolutions I will post re solutions. ;)* In mathematics the solution is the answer. Examples: x=42. Theta is 57 degrees. The price has increased by 15%. In statistics a solution provides something we can be reasonably sure of. Examples: We are 95% confident that the price of a house increases by between $5,000 and $7,000 for each extra bathroom, all other things being equal. The margin of error is 3 percent. There is evidence that more men prefer milk chocolate than dark chocolate. What is called a solution in operations research could be called an […]
27 December 2011

Templates for statistical reports – spoon-feeding?

Here is the poll for today. Indicate what you think, then read what I think. Reporting the outputs of statistical analysis is tricky. It is not easy to be both correct and readable. There are so many nuances that can make a seemingly correct statement incorrect. For example when reporting the R-sq value from a regression analysis, I have seen it written that “temperature explains 63% of sales.” This is almost correct, but should read “temperature explains 63% of the variation in sales.” There is a subtle but important difference (which can be the subject of another post!) For many […]
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 […]