Syllabus changes for January
Beginning with the January 2010 sitting, the syllabus has been changed slightly in that Pareto, Weibull, lognormal, Beta, and Chi-square distributions are no longer listed on the list of continuous distributions that you need to know. Despite this, some people have said that they still have seen questions on these distributions. In particular, this change doesn’t mean that those distributions can no longer be tested, but instead should mean that they cannot ask questions that require you to have memorized specific facts about those distributions. Other than the Chi-square distribution, I have never thought it was important to memorize anything on these distributions, so as a result, I don’t expect this to change the exam very much. There are a few Chi-square questions in the question bank that I think should be removed, but that doesn’t sound like it has happened, and there a couple lognormal questions that need to be either rephrased.
Of these 5 distributions, the Pareto and Weibull distributions are by far the most commonly tested, but the exam questions have always either given you the density (for a Pareto) or described the distribution as a transformation of an exponential (for a Weibull). In particular, the words Pareto and Weibull have never appeared on 1/P, and those questions are probably going to remain unchanged. The lognormal distribution usually comes up as a transformation of a normal, and again that is still testable as both normal distributions and transformations are testable. Finding the mean and variance of a lognormal only requires knowing the mgf of a normal, so that is still potentially testable but I think unlikely to appear. I think it is still worth watching the lognormal lesson in the seminar to see in practice how these transformations work. Likewise, the Beta distribution has almost always been tested by looking at order statistics of uniform random variables, and knowing about it can still provide you with some useful shortcuts there.
Wow – thanks so much for sharing that. I didn’t know that, and would have wasted my time solidifying my knowledge of those distributions. Now I can study much more efficiently.
I just started looking into your resources today. They look fantastic and I plan to use them for future exams. Your free video explaining the MGF clarified it for me better than the 3 other study guides I have been using.
That’s very interesting, because I trusted this information, and didn’t memorize Chi-square specific formulas. I am SO sorry I did.
I was sitting for P today and I DID have a question about Chi-square in my test. I can’t disclose the question, but it required pdf of chi-square and distribution was just named, no other information about it.
Puzzling…
That’s frustrating to hear. I haven’t heard of other questions requiring the pdf, or other people running into a chi-square recently, so there is a very good chance that this was a pilot question and doesn’t count. You can appeal questions within 2 weeks of the exam date by e-mailing [email protected] If you do so, I would include links to the Fall 2009 syllabus that explicitly lists “Univariate probability distributions (including binomial, negative binomial, geometric,
hypergeometric, Poisson, uniform, exponential, chi-square, beta, Pareto, lognormal, gamma,
Weibull, and normal)” as well as the May/June syllabus which replaces that list with “Univariate probability distributions (including binomial, negative binomial, geometric, hypergeometric, Poisson, uniform, exponential, gamma, and normal)”
I also sat for P on June 4 and didn’t study Chi squares. I had 2 questions about them, both about MGF’s. I felt a little blindsided by them, and didn’t have a clue what to do on the exam, after a little review at home, they were both pretty easy. Hopefully I will know for next time.
Ok, I’ve removed the comments from the Chi-square section that says it is no longer on the syllabus.