estimates 

according to some back of the envelope calculations, I need at least 40k € for a year to get anything done (this includes two persons working together, me and somebody else of equal skill level, and an office, no equipment) not really based on a Gantt chart, but whatever can be done must fit into this amount

re: estimates 

in practice, it would be like twice of that, because the estimate^ is just a lower bound
@dpwiz I can't use this kind of tools -- too complicated; generally my knowledge of probability theory is very rudimentary
@dpwiz somehow none of this makes any sense to me -- I only know what an abstract PDF is (a measure), a few examples (uniform, normal, log.normal, Poisson, etc.), and the usual concepts coming with it: mean and the higher moments (becoming tensors in multivariate PDFs), and CDF with their median and quartiles (one dimension), also how to combine probabilities of individual events according to the logical definitions in terms of the connectives (conditional probability, simultaneous, independence, and Bayes theorem included)
once upon a time I also wrote a program for least-square optimization (ERP-like)
I don't know anything about things like maximum likelihood estimation or chi-squared test, or how to apply anything I know from PT in practice

generally sophisticated statistical estimates feel like free money -- trying to get more precision from the same information -- well you'd need actual data for it to be valuable, and the estimates are just that: adding sophisticated theory on top of guesses doesn't make the predictions any more accurate

I might need the tools like Squiggle at some point, but I'd prefer them to be on-premise and not a webapp, and also if learning them I need to start from the very beginning, from the very basic practical examples
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@amiloradovsky squiggle is just a bunch of js, should work offline.

You don't need to have a statistics insight, just combine those intervals and get the risk profile: given X amount of resources I will fuck that up in Y% of cases.

@dpwiz how is it more accurate than just multiplying my guesses by a factor (3/2, 2, 4, etc. or conversely 1/2, 1/4, 3/4)?
if I say estimate how long (how many man-hours) a task will take, the only source of information I have is it's structure (WBS) and the sense of all the leaf subtasks being about the same size; I'm not sure how reasoning in terms of distributions may even help

@amiloradovsky those "hours" numbers, are lower/upper bound? Mean/median? Anyway, there's a missing variance information. And usually that's what screws your deadlines. Sufficiently high average numbers aren't actionable.

@dpwiz I'd think of them as being either mean or median
(usually I prefer thinking about mean, because it's easier to compute and may be generalized to higher dimensions, unlike CDFs)

thinking in terms of ranges would be more accurate indeed: say each subtask may take from x to y (hours), where we assume that the chance of it taking less than x or more than y is say <0.05 (or 1/4)
then from this we may compute the range for the whole task/project
naively one might just add the lower and upper bounds separately, but I guess statistically this wouldn't be quite correct

another question is whether assuming the distribution to be log.normal is always adequate

@amiloradovsky i think using lognormal makes sense given it represents the long tail of "ways this can go wrong" while yielding to central limit nicely.

I just thought that ELI5 of it can be something like "estimating order of magnitude". Something like "weeks" is anywhere from 7 days to a month.

@dpwiz re central limit: this kinda suggests that the distribution for the entire task/project has to be normal, or in this case log-normal Poisson distributions may also play a role here, contributing to the delays associated with failures, either of hardware or say sick leave of the employees

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