edX 6.00x – time for the final exam, but will MOOCs be bad for social mobility?

There’s just a day or so to go before the edX 6.00x final exam is opened up. There’s a 12 hour window to complete it in and the course team estimate that it will take around 4 hours of effort. I’m hoping to find some time to have a go at it over the weekend, but given the problems the course has suffered since the second midterm exam and that my grade is already a passing one, I can’t say that I’m all that enthusiastic about the prospect at the moment.

It’s not that the material presented has been bad. Quite the opposite – it’s certainly up to the standard of the ‘High Level Programming A and B’ courses I took at Warwick University many years ago as part of my computer science degree. With the possible exception of the course needing to devote a little more time to object orientation than the rather mad single week brain dump it tried to cover it in, it’s been well paced too.

The biggest problem has been the lack of leadership shown when things started to go seriously wrong with the schedule around 2/3rds of the way in. With hindsight, I fear that my “MOOC that failed to scale” rant in mid December was rather too accurate in its diagnosis of the key challenges facing edX if they really do want to be part of “the biggest single change to education since the printing press”.

Even before illness and personal tragedy had struck the (single?) member of staff attempting valiantly to keep the show on the road, key learning tools (finger exercises in the course jargon) had started to be omitted, problem sets were being issued late and incomplete, and a decision had been taken to cancel one of the 11 graded problem sets originally scheduled. In the event, another graded problem set was also dropped at the start of this year (on graph traversal problems – but it was quite good fun to do the ungraded version provided!) Even the graded problem set 9 which was eventually issued was rather perfunctory, bearing no relationship to the material the course had moved onto. Finally and belatedly, some real leadership was shown by the edX management and a fulsome and welcome apology was issued to participants.

For my own selfish reasons as a lifelong learner, I want initiatives like edX to be successful and useful. I’m taking courses such as those offered by edX purely for “personal development reasons”. As such, they are highly unlikely to benefit my future career success one way or the other. Free of charge is therefore definitely a good model for me!

However, I’m concerned that the hype surrounding MOOCs potentially threatens the diversity of provision in higher education for those that really need it. If governments around the world start to believe that more traditional HE institutions are not required (and I’m including established distance learning providers like the Open University in this bracket), we run the risk of narrowing not only the subjects on offer to our young people, but restricting academic freedom and innovation by concentrating power and resources in ever fewer, richer and distant institutions. Such a move would result in increasingly expensive in-person tuition for the few who can afford it, with a restricted online offer for those who are unable to pay – or unwilling to mortgage their futures.

Paradoxically therefore, I believe that the unintended consequence of the proliferation of MOOCs could be to reduce access to the kind of higher educational qualifications which can genuinely act as an enabler of social mobility.

edX 6.00x – Midterm 2 review

With Midterm 2 safely over, I can now reveal that I have just gained enough marks to pass the course – with a few more weeks of lectures and finger exercises, two more problem sets and the final exam still to go. That’s rather pleasing, so I hope no-one minds me sharing my progress chart below:

6.00x progress - after Midterm 2

6.00x progress – after Midterm 2

This time the midterm exam consisted of eight questions and was marked out of 96. I ended up with 92 – having reversed the answers for the EDrunk and PhotoDrunk random walks on question 6, losing 4 marks in the process. All in all though, it seemed easier than the first Midterm exam, which may just be a case of having had more practice with Python now I suppose, but I did manage to complete it in under 4 hours from start to finish. I would have been faster, but I took the test on Friday evening, so that necessitated a substantial break in the middle for dinner and wine …

As with the first Midterm, questions 1 and 2 were on definitions and this time I managed to think them all through *before* hitting the submit button. Question 3 was on statistical distributions and identifying which of a number of graphs belonged to particular datasets generated by a piece of code. Tricky, as the rules stated that you couldn’t simply run the code provided through the IDLE interpreter. I resisted that (huge) temptation and managed to identify them correctly.

Question 4 was on classes – with the final two parts of the question being the first two pieces of code that we were asked to write. These were a small change to the __lt__ method of a class and the creation of a generator function. Question 5 was another pencil and paper exercise on a fragment of Python code and again managed to resist the temptation to take the easy way out and use IDLE.

Finally, questions 7 and 8 both required more code to be written. Question 7 was a Monte Carlo simulation followed by the plotting of a histogram using pylab. The second part of this caused me a small problem, as it wasn’t clear that only the plotQuizzes() function needed to be submitted to the grader and not the generateScores() function which also needed to be written to support it! The error message I received on my first failed attempt hinted that this was the problem (something along the lines of not being allowed to use a random function call) and it went through on my second attempt. It’s clear from the 12 hours extension given for just this part of the exam that others had problems too (and also found other issues with the grader). Question 8 was on probability, with a fairly simple piece of code to write. Well it was simple, provided that you could solve the first part of the question, for which only a single attempt was allowed! Without knowing the correct answer (or being able to subsequently guess it), the coding would have been rather difficult.

Tonight I’ve finished the week 10 lectures – for which there currently appears to be no finger exercise posted. Past experience suggests that some may appear between now and Wednesday so I’ll keep looking in the meantime, just in case.

edX 6.00x – Midterm 1

With the deadline for the submission of the first midterm exam safely past, I’m now able to reflect on my performance here. 95/100 is respectable enough – although having dropped 4 out of 8 marks on the very first question, it wasn’t looking too promising early on Saturday morning. Note to self: read the question, read the question again and read the question again before submitting the answer for checking!

Fortunately I only lost one further mark (out of the 20 available for the sorting and complexity question) and managed all of the questions which required Python programs to be submitted (5 of the 8 questions on the paper) without any real difficulty at all – even though the final part of question 8 was a bit of a teaser. In real life, I think the way to have fixed the bug would have been to have thrown the code away and started again – with a solution that looked more like the second part of the question – rather than tweaking the rather strange code that was provided. But I guess the point of the exercise was to demonstrate an understanding of variable scope and how to pass functions as arguments to functions, rather than good coding style.

There was one question for which I’m particularly pleased with my answer, partly because  even though I’d not come across the puzzle before I managed to figure out an elegant and recursive answer in around 3 minutes!

The problem asked for a boolean function to determine if an arbitrary number of food items (I refuse to advertise the brand) could be packed exactly into boxes holding 6,9 and 20. For example, 21 should return True (9+6+6), whereas 7 will return False.

Recognizing that the problem is easy to solve recursively (i.e. for quantities of 20) led me to this solution outline very quickly:

If the quantity requested is less than 6, return False

else if the quantity requested is divisible by 3 with no remainder or the quantity requested is divisible by 20 with no remainder, return True

else return the value of this function for the quantity requested – 20

After I’d got to this answer I did try to think about how I might create an iterative version, but nothing I tried seemed to be particularly elegant. Searching the web after the exam had closed revealed a number of different iterative solutions to this and similar problems, but in this case, a recursive answer definitely seems to be both easier to understand and to program.

The week 6 material should be out later on today and we’re just about to get into the part of the course that wouldn’t have been taught when I was taking High Level Programming ‘A’ using Pascal at Warwick University in 1982 – object orientation.

It must be OU revision time again

Over the last few days, there’s been a steady increase in the number of people visiting my Open University ED209, DD303 and DD307 notes pages. It’s revision time, isn’t it? I knew there was something missing from my life this year!

Anyway, as I’ve been asked a few times about how I approached revision when I was studying for my psychology degree, I thought I’d collect all of my thoughts in this handy blog post. You may do it differently – and that’s ok as the first tip for revision I have is to make sure you do some – but do it in a way that works for you.

It’s worth reflecting on how much effort you put into TMAs when judging how much time you might want to set aside for revision. For example, if your course has 6 TMAs that (for the sake of argument) took you an average of 15 hours each, then a rough rule of thumb might be that you ought to consider 75 (6×15) hours of revision. After all, the OCAS (continuous assessment) and OES (exam) components are equally weighted on all of the OU psychology courses I took (with the exception of DXR222 which just had the examinable component and SD226, which had an end of module assessment in place of an exam – thank goodness!)

Having said that, it’s a good idea to work out how much time (realistically) you have to revise in and plan your revision around that time. I always found that setting myself modest revision goals was good (and by modest, I mean that if I achieved them I’d be able to answer at least one question from each section of the exam). I also found it useful to and to have a backup list of topics to revise once I was comfortable with my “must revise” choices. Looking back through my blog posts, it’s definitely what I did for DD307 last year and DD303 the year before that. In the end, the problem I had on exam day for both modules was too wide a range of questions to choose from … but that’s an infinitely better problem to have than having nothing to choose from.

I needed somewhere I could be quiet and spread my materials out. I found that our dining room table – even though it meant me having to share the space with our house rabbit (more of him later) was a particularly good place to work from for the final push. However, earlier on in the revision process I simply used anywhere I  could find a few minutes quiet to work from. Quietness was really important for me. I know some people say they work better to music or the background noise of a television, but I definitely can’t.

I always found that reworking the course material was important. It’s why I created my notes in the first place. With the exception of my DSE212 notes, I wrote them all while progressing through the module. I was almost too late on DSE212 before realising that it would have been impossible for me to revise from the books and scribbled margin notes alone. I tended to update my notes during the revision process and/or make handwritten summaries, flow diagrams and mind maps to go with them. You won’t find these online I’m afraid and I’m not sure I’ve got them still – and even if I had, no-one but me would stand much chance of deciphering them. If you’re curious, then have a quick squint at the photographs on this blog post. There are calming photographs of my house rabbit on there as a treat, as well as the notes!

Use other people’s notes to help too if you can find them. There’s the professionally produced ones from Linda Corlett and others of course, tutorial handouts are often useful and while it’s too late for this year to go on the OUPS revision weekend at Warwick University, it’s well worth considering attending in future. I also found having the support of a few study buddies incredibly useful as well – invariably meeting up virtually rather than face to face.

Practice essays, based on previous year’s exam papers (and particularly, spending some time writing good openings and closings) were another useful way I found of reworking material.

Which brings me onto handwriting. That’s something I hadn’t done a lot of since I left University the first time around in the mid 1980s. Being able to write for up to 3 hours, by hand, takes some practice. I found that I needed to train to be able to write for that long (perhaps not quite like an Olympic athlete, but you understand my point).

Just like athletes, having the right equipment is important too. For me, that meant investing in an endless supply of this pen. They’re fairly inexpensive – it’s all relative of course, as even at £1 or so for each one is way more expensive than free biros from hotels or pencils from a well-known blue and yellow themed household goods emporium. But they meant I was able to write for longer and  far more legibly than I otherwise would have been able to. In addition, they have the real advantage of being able to work sensibly on the “paper” the OU like to provide for exams. I learned the hard way on DSE212 that my nice fountain pen just wasn’t going to be able to cope.

There may be some other things that I’ve forgotten – and if so, I’ll add them in here as I think about them. And if anyone else would like to share advice, please feel free to add something in the comments. If you happen to be revising please feel free to say hello in there too.

I can’t believe that I’m writing this, but I’m really missing revising this year – and I’m sure that all of you who are definitely don’t believe me …

 

MITx 6.002x: post mortem 1

Now that the final exam has finished and the only thing that appears to be happening in the 6.002x forum is a lot of bickering about certificates, I thought I’d write a couple of posts to finish my journey off. This first post will simply look at how I did in the final exam. In the second post, I’ll reflect more generally on the experience and document what I thought was good / bad / indifferent about 6.002x as a whole.

The final exam had 10 questions, each with a number of different parts (1 mark per part), with 47 marks available in total. As I’d written in an earlier post, I needed to score 2/47 to ensure a pass and 34/47 to obtain an ‘A’ grade. In the end, I finished with 32/47 – a comfortable grade ‘B’ pass. Most of the questions I had difficulties with covered material from the first half of the course rather than the second half. I put that down to the second half of the course having become a little more practical in focus – in short, it contained the more interesting material!

Question by question:

1. Strain (5/5) – a nice simple resistive circuit problem to solve just to get into the swing of things.

2. Logic circuit (7/7) – another “gimme” as far as I was concerned. If I had a single criticism of the course content (and it’s not really the course’s fault, more my own expectations of it when I started) it’s that there wasn’t nearly enough digital in it. But at least there was a question on what little there was on the topic!

3. Switched capacitor (5/5) – straightforward stuff involving the calculation of a couple of different time constants. It took me two attempts to get all of the parts correct, as I hadn’t originally spotted that I’d need to re-calculate the time constant when the circuit was switched through the second capacitor … durr.

4. Bipolar Junction Transistor (0/9) – this is where I lost any chance of an ‘A’. It wasn’t really anything to do with a BJT – more a large signal analysis of a couple of voltage sources and a voltage controlled current source, followed by a small signal analysis. I got hopelessly lost and didn’t have the time to go back to first principles to sort it out. I still don’t think that it was a difficult or unfair question – I simply messed it up. Oh well.

5. Op amp with an RL filter (2/3) – straightforward, but I still manged to get the final part wrong as I’d missed out the RS resistor in the algebraic expression – I must learn to write more clearly.

6. Op amp FET (0/2) – I’ve no idea even now about how to solve this one! Hopefully the course team will publish a worked solution at a later date.

7. Trapping noise (3/4) – I have no idea what the part I missed out was asking for – otherwise, it wasn’t too bad a question.

8. Increasing Q (6/6) – no real difficulties with this one, apart from inexplicably multiplying one frequency by 2pi and not the other when working out the bandwidth on my first submission. I sorted that mistake out second time around.

9. Scope probe (4/4) – a repeat of one of the homework questions from a few weeks ago, just with slightly different values this time. Straightforward therefore.

10. Triode amplifier (0/2) – the course team weren’t joking when they said it was ” intended to stretch you beyond the material that we explicitly taught in this class” and “do not work on it until you have finished with the other problems.” More of a “WTF” moment than a “Aha” moment I think.

So 68% on the final exam; 86% overall. A very solid B and I’m pleased that I managed to stick with the course all of the way through.

MITx 6.002x final score: close, but not close enough

MITx 6002x - final score

The chart shows I gained a total of 86% overall – meaning I miss an ‘A’ by 1%. Rats!

As always, the questions I answered on the final exam seemed fairly straightforward and the ones I didn’t attempt seemed impossible! Even if I’d not made a silly mistake on one of the parts of the questions I did answer, I’d have still been short of the 87% mark by around 0.2% – and there definitely wasn’t another part question anywhere on the paper that I could have answered.

As the exam doesn’t formally close for some late starters until 1200 GMT tomorrow (11th June) I’ll leave my post-mortem until a later post. I’ll also reflect on the course as a whole. One of my original motivations for taking 6.002x in the first place was that I wanted to understand the strengths and weaknesses of the MITx approach as applied to teaching and having survived the experience over the last 14 weeks I think I’m in a much better place to write about that now.

All the best to anyone still grappling with the exam; congratulations to those who have passed and commiserations to those who have just missed out.

MITx 6.002x – almost time for the final exam

I’ve just completed the last homework (week 12) for 6.002x, so I’m running rather behind schedule as I haven’t even looked at the lectures for week 13 yet.  Normally, this wouldn’t be much of a problem, but as week 13 contains the final two sequences that could be tested on the final exam, I need to get a move on. Fortunately, in line with MIT practice, there’s no homework or lab for week 13. Equally fortunately, I’m very pleased that the Jubilee celebrations mean that I  have Monday and Tuesday off next week too!

All being well, these lucky breaks mean that I should get to the final exam in reasonable shape.

It’s going to be made available on June 6th from 2200 GMT (2300 BST) and will close at 1200 GMT (1300 BST) on June 11th. As with the midterm exam everyone has 24 hours from opening the paper to complete it, with 3 attempts per question permitted.

I’m currently 1.2% off the ‘C’ passing grade – which means I need to score just 3% on the final exam to gain my certificate. To obtain a ‘B’ I’d have to score 28%, with an ‘A’ available if I manage to achieve 72%.

Best wishes to everyone who’s going to attempt the 6.002x final exam next week. I wonder how many of the 120,000+ who originally registered for the course have made it this far?

MITx 6.002x week 10: (sine) waving but not yet drowning

This week’s lectures have been about the response of networks to a sinusoidal drive and how to analyse them. First of all, this involved using an incredibly difficult method based on solving differential equations (so difficult that the attempt terminates part way through after much baffling mathematics), a “sneaky” approach based on complex algebra and finally a “super sneaky” approach based on the impedance model.

This final method turns all of the steady state sinusoidal circuit analysis problems which seemed pretty difficult using the first two methods into problems which can be rather more simply solved by the application of Ohm’s Law, along, of course, with all of the usual circuit analysis techniques based on the node method, Thevenin, Kirchoff et al.

I think if we hadn’t been warned that the conclusion of the week was going to be relatively straightforward I might have been tempted to cut my losses and plough straight on into week 11 – but I’m glad that I didn’t. In the end, the lab and homework problems seemed to be fairly tractable once I’d thought about them properly – and been guided by the odd hint or seven from the discussion forum of course!

I now have the magic 59% mark showing up on my profile page – which, even if I complete the next two weeks homework and labs, I won’t be able to improve on until the final exam. Despite many pleas from students to the course team on the discussion forum, they still appear to be keeping silent about the form the final exam will take, when it will appear, how long we’ll have to complete it in and so on.

Not knowing when the final exam will appear is pretty frustrating, as one of the “joys” of being a part-time distance learner is that the rest of life tends to get in the way of study, in exactly the way it doesn’t when you’re full-time at a brick university.

One of the lessons therefore that the MITx/edX team ought to take from this first run of 6.002x is that certainty over the time windows for assessments at or very near the start of the course is essential. Without such certainty, it’s difficult to see how edX would ever get future students to pay for assessment, even if the delivery of course content remains free.

MITx 6.002x – midterm complete

It’s Saturday afternoon(*) and I’ve just completed the 6.002x midterm exam. In total, there were five multi-part questions, covering some basic circuit analysis (Q1), Thevenin and Norton circuits (Q2), a common gate MOSFET amplifier (Q3), a logic circuit consisting of a couple of inverters and a NOR gate (Q4) and a diode circuit (Q5).

Q1 – which involved finding a couple of node voltages and the power drops over resistors in the circuit, Q2 and Q5 were straightforward, although I confess it took me three attempts to get the Norton current right for Q2 (even though I managed to get the equivalent Thevenin voltage right first time – go figure!). Q5 was a repeat of an earlier homework question, but with slightly different values used, so it was pretty simple.

Q4 was a little trickier. I manged the first few parts of it easily, but then managed to over complicate the calculations for the falling and rising time constants so ended up taking a second attempt to get those values correct. I spent ages (and all three attempts) trying to work out the maximum power that could be used by the circuit, assuming it obeyed the static discipline. Eventually, I realised that only two of the MOSFETs could be on at the same time (rather than the three I’d assumed originally) and managed to get the answer right.

The question on the common gate MOSFET amplifier was, for me, the toughest of the lot. On the first attempt, I found that I’d only managed to get one part correct. Furious scouring through my notes, the textbook and a couple of other sets of notes from the internet saw me get three out of five parts correct on my second attempt. My final attempt saw me get four out of five parts correct. I’m kicking myself over the part I got wrong – as it was one of the large signal parts of the question and I’ve now figured out what I managed to mess up. D’oh, as a popular cartoon character might exclaim.

So my overall course progress now looks like this:

MITx 6.002x progress - after the midterm exam (and part way through week 8!)

MITx 6.002x progress - after the midterm exam (and part way through week 8!)

I’m part way through week 8 at the time of writing (and had got part way through the lab for week 8 by the time I remembered to take a screen capture of my progress), so unless I manage to mess the remainder of the course up spectacularly, the only question that remains is what level of pass I’ll obtain. I’ve set my sights on an “A” now of course, but I’d be happy enough with a “B” too. There was an ominous warning on the course information page a few days ago that the algebra and maths was about to get difficult again in week 9 …

 

(*) In compliance with the MITx honour code, the publication of this post was deliberately delayed and scheduled to appear well after the 30th April 1200 GMT midterm exam deadline.

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