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Verbalising mathematics

One thing that I think is very important to develop in students is their ability to describe mathematics, both verbally and in written form. I think that the ability to describe their thinking in a mathematically correct and concise way is a skill that can significantly improve the transition from GCSE to A Level in addition to the transition from A Level to University.
I recently stumbled on this activity on the Mathsbox website.

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I used this activity as a starter for a lesson with my Set 1 Year 8s. I gave them 10 minutes to work in pairs and write as much as they could, using the terminology we had been learning, to describe the figure in front of them. We then discussed as a class the various things they had come up with. I was really impressed with the language that my class were using, and it also allowed me to tackle some misconceptions with labelling angles, angles on a straight line etc. The key words at the bottom of the page were great for differentiation as some of the students didn’t even notice they were there and managed fine, but I could point them out to the pupils who were struggling.

I can’t recommend Mathsbox enough. I persuaded my school to buy their very reasonable subscription this year and they have some great activities for use as starters. Follow them on Twitter here. They also seem to have an open house for half an hour tomorrow (Sunday 30th November 2014) where you can try out their resources and activities!

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Exams and tests

I’ve just been marking some Year 7 end of term tests and I wanted to get people’s views on tests split up in to tiers.

I did two tests from different tiers with my class, and inevitably the levels reported by the tests don’t vary wildly.

To me, the whole purpose of summative testing is to get robust data. Why then do we not use as a matter of course one test that covers all possible levels, make it a bit longer and have everyone in a cohort sit the same exam paper. This approach would at the very least get rid of the “which paper will my students be able to get a C on more easily” debate at GCSE level. I also think that doing this throughout will lead to more robust data which is actually useful.

I’ve heard some arguments for having different tiers, such as students having lots of questions they can’t do being bad for self esteem.

What does everyone think? Do you have a preference?

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Teaching

The Perils of Grading Work

Last night, just as I was going to bed I was notified through Twitter of Manan’s (@shahlock) latest blog post where he looks at the grading (by another person) of some work that had been sent to him.

As he rightly points out commenting on just the written grading is fraught with problems as you do not have any idea of what has been said in class in relation to the work. I agree completely with everything Manan has said about this particular piece of work.

The assessor has been very thorough; looking at every line and not just skipping to the final solution. This is of course a good thing and should be applauded, as should the detailed feedback given. However, my initial thought on looking at this assessment and its grading was that it had been marked by someone slavishly (is that a word?!) following a mark scheme with less knowledge of mathematics than the person taking the assessment. On reflection, this is perhaps a bit harsh, maybe the focus of this assessment is exposition and explaining mathematical reasoning – this would explain some of the comments given for problem number 7.
I don’t feel that this explanation really holds for the other marks lost though. The “order of operations” one probably bothers me the most. Working out \(3(-7+9) – 5 \) by using the distributive property gives the same answer as calculating \(3(2) – 5\). Frankly who cares how this is worked out as long as the correct answer is given; it is a short calculation that doesn’t really require working out what is inside the brackets first! Similarly the marks lost on question 6 just don’t make sense…

I passionately believe that mathematics should be seen as a creative discipline (as well as a scientific one). This sort of grading completely goes against this belief and is only going to serve to diminish confidence and turn pupils off mathematics. We should be celebrating different ways of working things out and I think you can encourage and strive for correct written communication without being pedantic!

Please let me (and Manan) know what you think….

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A Level

Thoughts on A Level Mathematics and Making the Transition

Last night I read an excellent blog post by Stephen (@srcav) discussing the readiness of students for the current maths A Level. It turns out that this blog post was actually a response to another great post by Jo (@mathsjem) and I was going to comment on both posts, but then thought they would probably be a bit long for comments. So here are some of my thoughts…

The Importance of Algebra
As Jo points out it is possible to do well at GCSE without much of an understanding of algebraic manipulation. Algebra is, in my opinion, the bedrock of A Level, and students need to be able to perform algebraic manipulation correctly, confidently and quickly to do well at GCSE.
This appears to come as quite a shock to many students, who have got used to algebra questions being one of 4 main topics, and normally quite distinct from others. I have only been teaching at school level for a short time, however, to me a diagnostic algebra test at the beginning of Year 12 seems to be a very good predictor of A Level grades (far more so than GCSE grades) if the student doesn’t put work in to practice the algebra skills that they may be potentially lacking.

Timing
The choice of student’s applied modules seems to be important, and to me this choice means that an A Level grade is not really fit for being used by universities to compare students. M1 is a tougher module for a student to complete than either S1 or D1 and so an A Level where M1 and S1 have been chosen isn’t directly comparable to an A Level where the student has “chosen” (or pushed towards by a school looking for improved results) S1 and d!. The new 100% prescribed content of the new A Level should remedy this and enable the students to see maths as the connected subject that it is without the arbitrary distinctions placed on it.
Timing is also a problem for those students who are taking Maths and Further Maths. Ideally, a student could complete all of the standard A Level in Year 12 before studying Further Maths in Year 13. Where this isn’t possible students study Further alongside the standard A Level. Working on FP1 content whilst working on C1 content is obviously problematic as students don’t know all the techniques (polynomial division being one of them) that is expected for the Further Maths content. They also haven’t had the practice, or necessarily developed the mathematical maturity that is expected of them. This has obvious effects on confidence levels of the students, as well as creating time pressures when delivering the content.

Type of Exam Question
As Jo mentioned there is a large change in the wording of exam questions at A Level. I think that there should be greater parity between GCSE and A Level mathematics in this. I understand though, that this may go against some of the GCSE reforms to push questions towards simpler wording and grammatical constructs (as AQA definitely seem to be doing) so that students with weak language skills aren’t at a significant disadvantage in their mathematics exams. If we are taking students onto A Level who have achieved a grade B with less than 50% of the paper correct, it is entirely possible that students with weak language skills will end up taking A Level maths where understanding the exam questions could be problematic.
Students also sometimes find the use of more formal mathematical language and symbols confusing. This could be remedied by introducing some of this into the higher GCSE classes; for example sigma notation could be introduced when computing the mean of a set of numbers.

Managing the Transition
I believe that a mathematics A level is the most rewarding A Level a pupil could take, and so I, like all teachers I’m sure, want to make the transition from GCSE to A Level as manageable as possible.
In my school we set some summer work which is essentially revision of GCSE algebra, though it is clear that not all students have revised this sufficiently when they come to do their initial algebra assessment. This year I also sat the Further Maths students some harder work that was more open ended and of a problem solving nature. I wanted to stretch them and also get an idea of how their brains worked when faced with a challenge. These questions than formed the first lesson of the year. On the whole they were well received by the students with them saying that they enjoyed having a go at them even if they did not correctly solve them. This experience of struggling towards a solution is important. Many Further Mathematics students have probably never struggled with a maths question before and the increase in difficulty can sometimes be uncomfortable and hard for them to handle. Learning to fail and accepting that they will learn an awful lot in the process is an important thing to experience on the road to becoming a mathematician.
I’ve also found encouraging group work important too as this forces them to discuss the maths instead of working in isolation. Being able o discuss the questions and work through problems is important as there often isn’t enough time to talk through problems with all questions in class.

Off Syllabus Mathematics
Last year I was lucky enough to have some timetables time to work with the most gifted of the year 11 students, looking at mathematics that wasn’t on either the A Level or GCSE Syllabi. Due to my interests we looked at, among other things, floating point representation of numbers and round off errors, formulae for calculating Pi and iterative schemes for solving linear systems. Many of these topics are typically studied in Year 2 of an undergraduate degree, yet they were accessible to students who had just completed a GCSE course (of course some of the rigorous analysis was left out….). I am passionate about exposing students to maths outside of the syllabus as I think background knowledge often helps them see how to approach a question in a different light, or at the very least provides a motivation for studying what we do at school which is sometimes not explained enough.

A Final Niggle
One thing that I have always loved about maths is the “universal truth” that maths brings. A mathematical concept is always true no matter what, and something that you learn early on cannot be then shown to be rubbish. This is in contrast to the other sciences, for example in Chemistry when you learn about chemical bonding you seem to be forever told to forget what you have been told previously! For this reason it always pains me when teaching the quadratic formula that students begin to believe that getting a negative discriminant must mean they have gone wrong! I can’t see any reaso. Why a higher tier GCSE student couldn’t handle a question such as the following:

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I certainly don’t understand why complex numbers are not in the standard A Level as they are so fundamental.

Anyway, I’m looking forward to joining in with Jo’s chat tomorrow and looking forward to hearing other people’s views.

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TexWriter app for iPad

I am aiming to transition away from using a laptop at work, ideally going to using an iPad for almost all work whilst I am in school.

There have been a few sticking points that have prevented this, mainly

  • Lack of a decent LaTeX editor on iOS.
  • Inability to compile computer code natively on an iPad
  • Lack of equation support in Microsoft Office applications for iOS

Finally, I have found an app that can do most of the LaTeX compilation I want. In the past I have used TexTouch with dropbox syncing to compile remotely on my Mac, however the delays of sending files, waiting for compilation, copying back the pdf made this a fairly unwieldy approach, suitable only for quick and minor edits.

Recently I have discovered the TeXWriter app (http://www.texwriterapp.com/) that can compile LaTeX natively in the app without the need for an internet connection. First impressions are good; on loading the app you are presented with the following window:

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To compile your code it is a simple case of pressing the play button in the top right hand corner. Once compiled the output is viewable, as is the full LaTeX error report.

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I have tried compiling some fairly involved documents, drawing in many different libraries and TexWriter seems to handle it well. The only downside with this app is the time it takes to compile. A set of lecture slides that take less than 5 seconds to build from scratch on my MacBook Air takes over 3 minutes on my iPad. However this is an iPad 3 with only an A5X SoC, I’m looking forward to examining the performance boost when I get an iPad that is running with an A8 SoC.

I am also investigating the writeLaTeX service that runs in a web browser, though this does need a working Internet connection to compile. I’ll make that a subject of a further blog post in the future I think.

I always thought that Apple’s App Store terms and conditions prohibited code compilation, I’m curious to know how TeXWriter have got round this?! Unless it is because you aren’t generating an executable program…

At the moment TexWriter is definitely the best solution I have found for compiling LaTeX on the go on the iPad, however I need to see significant improvements in compile time before it replaces compilation on my laptop.

If anyone else has used TexWriter please let me know what you think.

Categories
Software

Getting to know Excel

Microsoft Excel seems to be a mainstay in schools for analysing and querying all kinds of data. Until last year I had barely used Excel since I, myself, was a pupil at school. Having spent years using Matlab to display, manipulate and interrogate data of many different forms.
Getting used to using Excel I’ve found many things that irritate me (not only the fact that it is often used for serious statistics when it shouldn’t be) and I find counterintuitive.

One of these is the behaviour of the LOOKUP function. In the simple example shown below I wish to examine a table of test results sorted alphabetically to find out who scored 56. A quick google suggests LOOKUP as a common way to do this, however as you see this doesn’t work.

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It doesn’t work because the vector in which we are searching for 56 is not ordered in ascending order, looking at the next screenshot you can see that sorting the table so that the scores are in ascending order does lead to LOOKUP working

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In general I am not going to want to re-sort a table just to do a bit of analysis and then re-sort again at the end – that is just a massive waste of time.

Instead I prefer to combine the INDEX and MATCH functions that Excel provides. These functions do pretty much what you would expect, without any strange behaviour:

  • MATCH returns the location of an item in an array. The first argument is the item we are searching for, the second the array in which we are searching and the third is an optional argument specifying if we are happy to accept a nearest match instead of an exact match.
  • INDEX returns the value at a given location in an array. The first argument gives the array, the second tells which row of the array to return. There is an optional third argument that specifies a column number, for example if I wanted the entry in a table at the intersection of the 2nd row and 3r column.

Combining these two commands we can build a function that does not require data to be sorted into ascending order for the output to be trustworthy. This is shown in the following screen shot

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I think I will now very rarely use the LOOKUP function, or VLOOKUP.

As an aside, the screen shots shown are from the iOS version of Excel, which actually has pretty good functionality. I’m not a fan of Microsoft products, being a Mac guy, but the iOS Microsoft Office apps are actually really good. I’m trying to shift to doing a much work as possible on my iPad now (not being able to always find a computer at school in free periods) and I’m sure I will blog about other apps that I find particularly good for the iPad.

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Explaining what maths is in a tweet…

During this weeks #mathschat @LearningMaths posted something like “it comes down to what we think maths is”.

This gave me the idea of trying to crowd source a definition based on peoples tweets. I follow a wide selection of mathematicians, maths teachers, computer programmers so I think I could get some interesting responses.

Please tweet to me (@DrBennison) your definition of what mathematics is. The only rule is that it must be no longer than a tweet, i.e. 140 characters.

My attempt is the following

A creative discipline with problem solving as a focus; to expose truth and beauty in the world around us in a rigorous, reproducible way.

Sounds a bit ….. I’m sure you can all do a lot better than me! I look forward to seeing your tweets.

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Everything We Know Is Wrong

On Tuesday 26th August 2014 BBC Radio 4 presented a programme looking at the validity of scientific research. This programme is Everything We Know Is Wrong, available on BBC iPlayer here.

Jolyon Jenkins presents, among others, the results from some research done by Dr. John Ioannidis of Stanford University. His paper “Why Most Research Findings are False for the journal PloS Medicine surveyed 50 of the most cited (more than 1000 times) papers in medical research. For each paper, he tried to find if there was a subsequent study that was larger to back up these cited papers. 5 out of 6 of the papers whose results had been based on non-randomised data had been proved to be wrong, yet these papers were still being cited. In addition, about 25% of the claims based on randomised data have been shown to be wrong or widely exaggerated.

This issue of reproducibility is important to me, and something I feel is a major problem for educational research. As a numerical analyst, generally when results are presented in a paper it is possible to go away, write some computer code and reproduce the computations / results, checking their validity. This does not seem possible with any of the educational research papers that I have read. For a start data is often anonymised (even if it is from the public domain) and so cannot be verified. Not only this, there are so many factors at play in a classroom it is hard to strip everything out apart from the factor the researcher is interested in. Another problem is mentioned in this programme: many papers seem to use very small samples, to me this throws into question the power of the test. Has the conclusion presented in a paper really been found, or is it just by chance.

Of course, their are ethical considerations (leading to the use of anonymity) and cost considerations at play here, the larger a sample, the larger the cost of the study and os the less likely it is to be funded, especially if the outcome is unclear.

John Ioannidis also discusses the influence of the culture of scientific research in what is published. Having spent a few years of researching a topic, it is not ideal to have nothing to publish, and so, if the original outcome hasn’t been realised researchers may start looking for something in the data to publish, even if the study was not designed to investigate this. This I am sure happens in the field of education.

Academic researchers, in all fields, build their career on their publications. This leads to a pressure to publish results (potentially limiting the time spent verifying a theory) and also means that previously published results are very rarely checked – You are not going to get a blockbuster publication by re-doing the work of others and verifying it. Even if some work has been checked and shown to be wrong, this fact may not be published. Suppose that a new researcher, R, has shown that a result due to a big name in the field doesn’t hold. How would publicly criticising an acknowledged expert in the field affect this researcher’s career? The big name may even be on the refereeing panel of R’s paper – is this going to be fair?

All of these issues should be considered when reading a piece of educational research. It is important to not take research at face value without first passing a critical eye over it.

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Integration by a flowchart.

After years of dealing with any integrations that I had to do by thinking “let’s load Mathematica” I thought I should probably practice doing some by hand as I will be teaching Further Mathematics this year and will need to be able to integrate by hand.

As I was practicing a few I had a vague memory of a flow chart that my A Level teacher had given me (a long time ago) and thought it could be useful to try and produce something similar.

I had also just downloaded the iPad Grafio app so I decided that producing a flow chart for integration would be a good way to get used to Grafio. Overall a fairly easy app to use, sometimes a bit fiddly though to place content where you want.

The flow chart is shown below:

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And a high resolution pdf can be downloaded at the following link.

Anyway, I would be very grateful if you commented and let me know what you thought of the flowchart. Do you work through a similar process when integrating by hand? Have I missed anything that you think is important?

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The Educators – Episode 2 John Hattie

This Wednesday (20/08/14) Episode 2 of the new BBC Radio 4 series The Educators aired and is now available on iPlayer. In this episode Sarah Montague interviews John Hattie, Professor of Education at the University of Melbourne about his work analysing a wide range of educational research.

John talks about his work analysing over 60000 studies (encompassing a quarter of a billion students) to find out what has the largest impact in improving the educational outcomes of students. This work took him over 15 years and is probably familiar to many through his books on Visible Learning.

In the programme, which is well worth a listen, following interviews of parents discussing what they look for in a school, Hattie makes the comment that they focus on what they can observe; things like class sizes, leadership of the school, Ofsted reports and whether children appear happy in the school. Hattie points out that these are poor proxies for what is really important – the quality of teaching. I, as a teacher (and I’m sure mos teachers too) agree that it is the the teaching that makes the difference between success and a pupil not achieving their potential.

Hattie lists many things that actually have zero or little effect such as class size, homework (greater effect in secondary schools than in primary) and the type of school. All things commonly held to be important. This is all discussed in more detail in his books, with proper references to the original studies and comments on the validity and quality of the studies looked at.

On the subject of the quality of the study he made one comment that I found fairly strange:

If the effect is quite large, then the quality of the study is not that important

I really don’t agree with this, I could make up any old junk and get a large effect size, but surely the validity of the method used in a study is important to whether the study and it’s conclusions have any value! Not being a statistician, I don’t feel qualified to critique Hattie’s methodology, though I would be amiss to not point out that such criticisms do exist. Some of these, including the use of the concept of effect size are discussed in the blog of @OllieOrange2. As I say, I am not a statistician and am also a big fan of Hattie’s books and research, but some points raised in this blog do raise concerns that at some point I should look into in more detail.

Hattie makes two points that struck me in this programme: 1) The biggest predictor of future health, wealth and happiness in the future is the number of years in schooling, not achievement at school. 2) In excellent schools there is a dialogue about the teaching and the impact that teaching is having.

I would recommend this radio programme and John Hattie’s books to all teachers, wishing to investigate what makes a difference in schools. However I would echo Hattie’s remark that he is not giving school leaders a recipe for what they should do, rather he is giving them a way to think – to investigate the impact teaching and decisions have in their school.