Hi Serap, With regards to your question on how to get the parameters of the truncated distribution, the following: When you fit a Weibull distribution to your...
Not sure if you have noticed the previous email, but here are some inputs: 1. CB distribution fitting does not fit to truncated distributions. Huybert's...
Hi Guys, I'm using the CB Predictor for predicting Weekly Revenue based on 9 Years historical weekly revenue data. Until Q3-2008 I had great accuracy in terms...
Using past data to project future results only works if you have reason to believe that the future will be like the past. If you think we are in different...
Hi Milos: Eric has a good point... I would add that you may have to build an econometric model to figure out what your upcoming demand will be based on what is...
I think this is a good time for researching on a good econometric model, as Eric suggests. You might want to consider a few macroeconomic industry-specific...
I have been wondering what types of statistical distributions this group is using in their simulations... It seems that I tend to use the triangular...
JCR, Great questions. A common way we tend to explain distributions is that there are distributions that are typically used to (1) model 'expert opinion' and ...
Those that know me will have wondered why it has taken me so long to respond to this. The basic philosophy I use is to use the "simplest" distribution that ...
To Bill's arguments I would add one test that I've used many times when a subject-matter-expert tells me, "We have no idea other than the endpoints; therefore,...
Uniform distribution does has its function in real physical situation. Suppose you need to model the imbalance force of a rotating fan which is a vector...
First and foremost, many thanks to all of you for your responses! Bill's answer got me thinking, and I must confess I never really gave a deep, hard thought...
This seems like a simple question but I cant find the answer: How do you enter a custom continuous distribution, such as f(x) = 3x^2 for 0<x<1? Thanks...
Jeffrey, Although it indeed sounds like a simple question, the answer is not that easy to find (you have to use the Custom Distribution in a very special way)....
Hi Huybert- What do you think about this alternative solution: Set one cell up as U(0,1) and another has a formula based on setting U = F(x) and solving for X....
Hi Jeff, Thanks for the email - that would indeed work very well in this situation. This is in fact the way that CB generates random numbers from most of its ...
How do I get Crystal Ball to provide the mode of the forecast distributions? In the summary statistics the mode is shown as "-". Greg Greg Pelletier Department...
Hi Greg, Crystal Ball doesn't provide the mode of the forecast distributions if the forecasts are continuous because the estimate of the mode is quite...
If you had any continuous distributions on the input side, the probability of getting the exact same output value more than once is essentially nil. Since the...
Am I correct in assuming that the input parameters for the "Define Assumptions" for a Lognormal distribution are the arithmetic mean and standard deviation...
The default options are arithmetic, although the inputs can be changed to either geometric or log via the Parameters menu in the distribution window when...
Hi, Greg, It is true that the mode of data has little use and can be ambiguous or misleading. Further, we know that outputs of simulation models are presented...
Can someone provide an explanation of how Crystal Ball is calculating the "contribution to variance in the sensitivity charts? The CB help and also model...
Hi Greg, Great question. You are right, that is indeed the way that Crystal Ball calculated the Contribution to Variance. To make it easier to understand/see,...
I have two columns of data. The leftmost column is my variable of interest which is continuous (e.g., income), the other is the weight to be given to the...
I am trying to perform a Crystal Ball simulation that models a securities portfolio's performance over a 30-year period. The portfolio contains 7 asset...
Hi Amy, Thank you for the email. If you follow the exact procedure you described below, the mean of the Custom Distribution (with the two columns) should be ...
Hi Huybert, Thank you for your reply. The sum of the weights is 1 and I have been running 50,000 iterations. So I'm at a loss. I am using CB 7.0 on Excel...
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