Since the previous report, the Summary sheets for the updated D.1, D.2, and D.3 have been completed, and are available in the Before You Begin section of the course.

Today I finished reconstituting the problems sets for the new lesson based on the old lesson problem sets, with many small updates to the problem typed solutions.

There was a significant change to the way that the new lessons handle the F-test from the old lesson D.3.6 and D.3.7 to the way that it is now handled in D.3.3 and D.3.4.    The new way is simpler and easier than the old way, and it also more closely conforms to the method used in the Dobson textbook source material.

Because of this significant change, the solutions to the problems in new D.3.3 and D.3.4 are pretty different than the old solutions.   Since some folks have already learned the method in old D.3.6 and D.3.7, I’ve left the existing copies of those problems that required updating in those lessons, and added new copies of those problems with updated typed solution into the new D.3.3 and D.3.4 lessons.  As a result, there are now a few duplicated problems in the problem system with different answers.    I don’t know of a good way around this without insisting that everyone learn or relearn from new D.3.3 and D.3.4, so my plan is to leave things this way until the next sitting passes.   Please be aware of this situation when you are practicing problems – each problem tells you which lesson it is from, so if you see a problem that you think you know how to do and the typed solution is completely foreign, check the lesson that the problem is from to see if the reason for this is that the problem is from the lessons that you did not use.

Next on my list is to update the Flashcards for new D.1-D.3 (B.4 is already done), fix the solution tab to reflect the updated problems, and add the relevant problems from the past Exam S sittings into the lesson level pdf problem sets and the practice system.  A bit later on, I also plan to update the Review lessons for B.4, D.1, D.2, and D.3.

I’ve just uploaded the last new video for lesson D.3.4, and with that, the updated D.3 lessons are complete.

D.3 has undergone the most significant changes of the D.1-D.3 set.

First, the old D.3.4 lesson on estimating GLM models moved (with a major overhaul as well) to the new D.2.3 lesson.

Second, I elected to remove the discussion of the score statistic from the old D.3.1 lesson.  This is a topic that is not covered in a clear way in our source text, and the examiners for MAS-I and Exam S before that seem not to have any interest in the topic – with good reason, I think since I don’t think anyone actually uses the Score statistic for model testing.  The Score is useful for the GLM estimation procedure in D.2.3, and it is only in that context that we have seen it appear on the exam, so that’s where problems relating to the score will be found for the updated lessons.

The next change concerns Prediction intervals.  The old lesson D.3.5 included formulas for Prediction intervals in the multivariable normal and the single variable regression case, even though these formulas do not appear in our source texts.   Since the formulas have not been needed since the change from Exam S to MAS-I, I am now confident that these formulas are no longer required.  They do appear in the discussion of prediction intervals in the new lesson D.3.1, but without the need for computational examples, the overall content of the old D.3.2 and D.3.5 has now been combined into a single lesson.

Finally, I’ve significantly simplified the presentation from the old D.3.6 and D.3.7 lessons into the new D.3.3 and D.3.4 lessons.

I’m very pleased with how all of the new lessons have come out.  I believe that these new lessons are more clear and more focused on the aspects of the syllabus content that are of the most interest to our exam writers.

While the lesson updates to B.4, D.1, D.2, and D.3 all complete, there are many auxiliary items that need attention.   So for the next bit, I’ll be working on the lesson problems, summary sheets, flashcards, and review lessons for these sections of new lessons.