I thought I’d give you an update on the whole frequency tree “thing” that happened when the original Sample Assessment Materials from the exam boards were published. It originally started here when I (“they” made me do it!! .. bloody twitter people!! .. yes you! you know who you are!) took the “Michael” a bit, and it seemed to run and run – it was even mentioned several times at various events and still makes me chuckle!
However, I did say that I was happy to be “put back in my box” and so it turns out that they are real .. My mam always told me its a good thing to be able to admit when you’re wrong … so AQA I apologise! Genuinely.
Shortly after I published the above post, Andrew Taylor (Head of Mathematics at AQA) got in touch via email and explained the rationale for inclusion being that “many of the teachers we spoke to were initially unfamiliar with the term and that is one reason why we felt it was important to put a question on the specimens”. He also referred me to a blog by a David Spiegelhalter who had commented on his blog in relation to the inclusion of frequency trees in the new programme of study, that it was good to see “reference to ‘frequency trees’, ‘expected outcomes’ and ‘expected frequencies’, since hopefully this will encourage the teaching of probability through expected frequencies”.
Weeeelllll … I couldn’t leave it there could I? So I got in touch with David Spiegelhalter (who must have one of the longest job titles ever:”Professor for the Public Understanding of Risk”) and it turns out that he knows his stuff – he told me about a document he’d put together with “some sources on frequency trees and general use of ‘natural frequencies’, including icon arrays. The academic work has been mainly done in experiments on adults in a health setting, although some educational work is reviewed in the Kurz-Milcke paper. The use of natural frequencies for explaining uncertain outcomes in health is now almost universal – e.g. “out of 100 people like you, we would expect….”. See for example the latest breast screening leaflets.” He was also able to point me in the direction of the NRICH site which has a detailed exposition, emphasising the use of frequency trees for recording multiple experiments as a stage before getting to probability trees.
Some of this, I have to be honest is beyond little ol’ me but I get the idea from the Nrich site and it is a way that I will probably use en route to probability trees, but still not convinced that they should be an explicit examined topic… but hey ho .. as the phrase goes “sometimes you teach what you want to teach … but most of the time you teach what you have to teach” .. .oh my! that’s wrong …. but I like it!
I think that’s me in my box do you agree?
PS: Yes … still on holiday!
PPS: I still find it amazing that my little blog would prompt any kind of response. Nearly 2 years into blogging and I still get blown away that people want to read this shiz! Thank you!!!