Thursday 10 October 2013
'The Sticking Points'
This is is a blog post to summarise the kinds of issues that people are coming up against as some of us go through the IA process for the first time with the new syllabus. For Southern Hemisphere schools it must be coming soon for you too. There is no getting away from the fact that attention to detail is always important but will be even more so as we get used to the modified criteria. Likewise there is bound to be a period of adjustment. All we can do is our best and make sure we pay attention to the information we do have. There are lots of details available in the course guides and plenty more on this website. I have included some links below. For that reason I am just going to focus on the some key reminders.
This is a big one. The marking criteria will penalise irrelevant processes. As such, students should take care to concentrate on quality over quantity. Remember the minimum requirement is two simple processes and one further process. This is not a huge amount, so it is reasonbale to expect that they are relevant to the question. I would advise students to make sure they have justified the relevance of their processes. Likewise, I would advise teachers to include notes with their sample that show clearly how they have considered relevance as an issue.
For exams, the emphasis has shifted to 'p-numbers'*(see update below), thus removing the need for calculating the chi² statistic and comparing it with critical values. For projects though, students should still be demonstrating that they know how to calculate the chi² statistic and compare it to a critical value if they want it to be considered as a further process. I can't find this officially documented on the OCC (yet), but it has appeared in workshop material. It makes sense, since the alternative would be to have students get the p-numbers from their calculators which would not be consistent with the need to show the mathematics of the process.
In addition to this it is important to note the change of stance on expected values - NO EXPECTED FREQUENCIES OF LESS THAN 5 is the new rule where previously it was no more than 20%. I can see students and teachers getting caught out on this one.
Another key point is the requirement that if students have 2 x 2 contingency tables, they must apply Yates's Continuity Correction. This, particularly in combination with the above, will catch people out too. Students may well set out to have bigger contingency tables, but then have to combine them to avoid expected frequencies of less than 5 and possibly end up with 2 x 2 tables.
There is a specific requirement that 'the sampling process is descibed' where students have used secondary data. This is likely to present some problems. In many cases, there is no need to sample, especially since the use of technology clearly enables large amounts of data to be processed and thus give a more representative result. If this is the case then I will be advising students to make this argument and say that sampling was not appropriate. That said, I think a really thorough discussion of how, what, why and where, concerning their data is a must and in doing so students will be talking about how and why they selected the data they went on to use. I would suggest that students bare sampling in mind when they are looking for secondary data. For example, if a student chooses to collect data on different countries, then there is ample opportunity for them to sample the 200 + possibilities down to 100 from Africa and Europe so that they might be compared and thus focus the survey by doing so. Students might compile a large data base and then take samples from it for a given aspect of the project.
The most difficult scenario is the one where a student only has 50 items surveyed and any sampling will reduce that number to one that is too small. For example a student might do a questionnaire and get only 50 responses. A solution here might be for the student to describe the sampling in terms of the people they offered the questionnaire to.
The aim is a good one and will help us to encourage students to do as I have suggested above.
Notation and Communication
With these being separate criteria now the requirements have effectively become a little more demanding. I will be advising my students to pay very close attention to detail on notation. I will probably provide them with a list of potential pitfalls like...
My point is that previously, 'Structure, notation and communication' were worth 3 marks, now they are worth 5 in total over the two separate strands and so there is more to lose by missing some important details.
There are obviously many more things to think about here and there are more details on both the OCC, this site and other places, but I just thought I would write a little about the things I thought would be more common concerns.
Make sure you check out the teacher support material on the OCC. There is a nice section where the marking criteria are shown with links to examples of projects that got those marks. I will be making reference to this in my moderator notes.
On this site, I have done a detailed elaboration of the Marking Criteria that makes a direct comparison between the old and new syllabi. There is a whole host of resources about the whole IA proces in the IA section.
I wrote this because a few people I know have asked me questions about this in the last few days. As the site says, I am not representing the IB and, like many others, doing my best to be as well prepared as I can be for my students. I am the author of an extensive site about IB Maths Studies. I am an experienced workshop leader for IB Maths Studies and a moderator for the Internal Assessment. Perhaps more importantly than that, I am a full time teacher with Maths Studies classes.
Anyway, I hope this was useful - writing it certainly was!
*Update on chi2 tests - Following an exchange with one of the users of this site, I can see that I haven't been quite clear about this regarding how it might be tested in exams. It is quite possible that students will be asked to calculate the chi2 statistic and compare it to a critical value in and exam BUT if this happens then the critical value will be given. It is also possible and I think, more likely, that students will be asked to conclude on chi2 tests using the p-number from their calculator.