Thursday, April 18, 2013


It's liberating to be free of a textbook. Yes, the course has an online text, and it's a great resource, but I'm not really following it. I do end up following it because my usual sequence of topics and the sequence in the text are both heavily influenced by Statistics (fourth edition), by Freedman, Pisani, and Purves.

Mostly, though, I'm free to teach what I want, and the students are free to use any support materials they find helpful. So they are referring each other to assorted online sites, collecting materials on the course wiki, simulating on the computer, using algebra – whatever works.  In a group as large as this, the list of whatever works is long.

With the web as their library, Stat 2X students are more open in their approaches to learning and problem solving than I usually find in intro courses on campus. Undergraduates who have to spend lots of money buying assigned textbooks tend to get rather annoyed if the course strays too far from the text and its methods.

But then comes the Stat 2X clamor for, "More practice problems!" and I find myself wishing I could just refer students to the appropriate section of a text. Philip's text does have assignments, and we're working on how to make those available to tens of thousands of students; but as they're not exactly in sync with the lectures, I'll have to spend some time selecting the right ones. I can't use problems from other texts for obvious copyright reasons. So I have to make my own.

Which is a hugely time intensive job ... the hardest part of creating course materials, by far, specially since I also have to write out the solutions.

Time is the resource in shortest supply. Students ask me to "please post more problems," as though I have them sitting around somewhere, all ready to be uploaded. But I don't. I solve lots of problems in class on campus, and the students and I solve them on the fly, and it's fresh and interesting and ... unrecorded. Somehow I'm going to have to create some hours to make sure students get more practice problems for their upcoming midterm exam. There better be eight days this week.

The next time I go through Stat 2X (students keep asking when, and I have no idea), I'll be able to focus largely on the exercises, and then I hope there'll be a large enough stash of them that I'll essentially have produced my own "book". Maybe I'll call it a mook.


  1. I love Introduction to Counting & Probability for this week's topics, from the Art of Problem Solving , by David Patrick

  2. I'm currently taking Stats 2x as a refresher, my last serious contact with statistics was back at university in a freshman course 10 years ago. Wait. Make that 15 :)

    Compared to other online courses I have taken, Stats 2x provides a rather large number of exercises, which is key to understanding in my opinion. I like the quizzes and I do every single one of them, trying to get a perfect score (that's how I'm wired, when I play I play to win). I really, really appreciate all the work you put into this!

  3. Coincidentally, 'Mook? (What in heaven's name is THAT!?)' is also what I'm asked when I tell people about the course!

  4. It's also liberating to be able to pause, and repeat a section of the video lecture as well. I find the entire process of the online course to be much more flexible.

  5. Hi Prof A
    I think that it is great that you are liberated from text books because the simplicity,quality and clarity of your lectures is truly outstanding.
    I last learned Stats in IIMA in 1972 -- so you can imagine how worried I was,but you have been a wonderful help.

  6. To Prof. Adhikari,

    (note- I'm taking Stat 2.2X currently & also cross-posted this comment on our course Discussion Forum) I read Prof. Adhikari's blog post, where Adhikari notes that many of us edX Stat 2.X students have been asking for additional problems. However time is a limited resource for Adhikari, TAs, etc. This is a free open-source pdf book, "Stat 101 textbook". I read that is a good textbook, & recall that it is integrated with R code examples, for those who also wish to learn R alongside the Stat 101 concepts. I downloaded this textbook, & noticed that it has 1 end of chapter exercises for each chapter 2 Appendix A, which has solution to all odd-numbered end of chapter exercises.

    my recommendation: to pair each existing Adhikari lecture problems (for example lec2.3 Sampling Without Replacement- The Hypergeometric Formula p12of 30 "Simple random sample")


    1 or more relevant OpenIntro odd-number end of chapter exercises

    It would be great if Adhikari or the TAs could spend time on this. If not, perhaps some students could do so, & Adhikari/TAs could "verify"/"quality check" that the pairing is indeed relevant/appropriate.

    In addition, perhaps for a subset of "verified" OpenIntro problems, video "whiteboard" solution mp4 files could be made for these problems (Note: page says some "Videos are coming on May 6, 2013", so maybe some useful OpenIntro videos may already exist in time for a future offering of Stat 2.X).

    Perhpas a section could be added to the Stat 2.X wiki page for Staff & students to list & verify these pairings to OpenIntro problems.

  7. I greatly appreciate the time you've given to provide us with extra practice problems (and solutions!). They've been very helpful.

  8. Hi Prof A
    First of all, I would like to thank you the work you did in the Stat 2x course. I am learning not only stat but your methology of teaching as wel, and, by the same way, I´m improving my English level.
    Kisses from Basque country