Course 3: (a,b,0) Class

[bg23516]

I'm going through Mahler's notes, and I've come to the section on the (a,b,0) class of frequency dists, which gives a formula for calculating the ratio of f(x+1)/f(x), so you can determine a result numerically.

How important do people feel this is? Especially those who took the exam in the past... Has this stuff been useful?

Thanks.

[Elisha]

There could be 0-2 questions on the exam on this. Worth knowing if you have the time.

[Howard Mahler]

There have been no specific questions on the Course 3 exams that have been released, using the (a, b, 0) formula.
There has been one question on Course 4, 5/00 Q.40, related to "accident profiles". (See problems at the end of my section you are discussing.)

Thus while the Loss Models textbook spends some time on this, it is only one of many facts it is helpful to know, rather than being very important.

Of course there are many formulas and facts on Course 3, and to pass most people probably have to know a fair number of them, including some of those that are less than very important.

If you plan to be better than average on frequency distributions this is one formula to learn. (One has to be better than average on some topic(s) in order to pass, unless one is very lucky.) The other ideas in my (a,b,0) section, besides the formula itself, are also worthwhile if you plan to be better than average on frequency distributions.

Howard Mahler

[Smash Puny Human]

I think that I remember using the formula for f_s developed for the (a,b,0) distributions. Also there was a question from May 01; if you recognized it was Poisson you could do it without the (a,b,0) recursion. Lastly, some of the distributions on the exam handout give you p_0 and the values for a & b. I don't think that it was a waste of time to learn. Who knows what they will decide to put on the next exam. Good luck.

[retaker]

Didn't they take that off the syllabus. Duh. :o

[Toonces]

Retaker, I believe they took (a,b,1) distributions off of the syllabus

[retaker]

Okay, then I deserve the Duh!

[Howard Mahler]

As stated by Smash Puny Human, Q. 25 on the 3,5/01 exam, can be solved by either using the
(a, b, 0) formula or by recognizing that it is a Poisson.
(That question is the last problem in (a, b, 0) class section of my study guide on Frequency.)

So the (a , b, 0) class and formula are still on the Syllabus and can help you to answer questions on the exam.
The formula can also help to quickly caluculate a series of densities at 0, 1, 2, 3, 4, etc.

Howard Mahler