18 March 2013

Confidence Intervals: informal, traditional, bootstrap

Confidence Intervals Confidence intervals are needed because there is variation in the world. Nearly all natural, human or technological processes result in outputs which vary to a greater or lesser extent. Examples of this are people’s heights, students’ scores in a well written test and weights of loaves of bread. Sometimes our inability or lack of desire to measure something down to the last microgram will leave us thinking that there is no variation, but it is there. For example we would check the weights of chocolate bars to the nearest gram, and may well find that there is no […]
10 September 2012

Why resampling is better than hypothesis tests and confidence intervals

I love to read George Cobb’s writing. In person I found him a kind and intelligent man, and a generous host. But his writing is laugh-out-loud funny at times, provocative and inspiring. I suspect that he may be the indirect cause of near civil unrest among maths teachers in New Zealand. The link between George Cobb and mathematics teachers’ concerns is resampling. I will provide some background, then explain. The New Zealand curriculum is divided into eight learning areas, one of which is called Mathematics and Statistics. The separate acknowledgement of Statistics, which I believe occurred in 2007, is indicative […]